Automotive glass compositions, articles and hybrid laminates

ABSTRACT

Embodiments of glass articles comprising an anneal point (° C.) and a softening point (° C.), and the relationship of (anneal point+softening point)/2 in a range from about 625° C. to about 725° C. are disclosed. In one or more embodiments, the glass articles include a glass composition including SiO2 in an amount in a range from about 63 mol % to about 75 mol %; Al2O3 in an amount in a range from about 7 mol % to about 13 mol %; R2O in an amount from about 13 mol % to about 24 mol %; P2O5 in an amount in a range from about 0 mol % to about 3 mol %, and one or both of MgO and ZnO. Laminates including such glass articles, and methods for making such laminates are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 16/002,276filed on Jun. 7, 2018 which claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/523,395 filed onJun. 22, 2017, the content of which is relied upon and incorporatedherein by reference in its entirety.

BACKGROUND

The disclosure relates to glass compositions and laminates, and moreparticularly to glass compositions, glass articles and laminatesexhibiting bending properties for use in automotive and architecturalapplications.

Glass is used in windows due to its optical clarity and durability.Automotive and architectural windows (or glazing) may include a singleglass article (in sheet form) referred to as a monolith, or a laminatethat includes two glass articles (in sheet form) with an interlayer of apolymeric material disposed in between. This glazing can be used as awindshield, side lite, rear window, sunroofs and the like in automotiveapplications. Architectural applications may utilize similar glazings inbuildings, panels, walls and the like.

As shown in FIG. 1A, the method of making a curved or shaped laminatedglazing includes forming two glass articles 10A, 10B (typically sodalime glass (SLG) sheets made via a float process), cutting and finishingthe glass articles 20A, 20B, placing one glass article on top of theother glass article and heating the stack of glass articles to atemperature (“sag temperature”) at which the glasses sag together to thedesired shape. As used herein, “sag temperature” means the temperatureat which the log viscosity of the glass article is 9.9 Poise. The sagtemperature is determined by fitting the Vogel-Fulcher-Tamman (VFT)equation: Log h=A+B/(T−C), where T is the temperature, A, B and C arefitting constants and his the dynamic viscosity, to annealing point datameasured using the bending beam viscosity (BBV) measurement, tosoftening point data measured by fiber elongation. When glass articlesare sagged together when stacked on top of one another, the process isreferred to as “pair sagging”) 30. In one or more embodiments, themethod further includes separating the two pair sagged glass articles(typically after the shaped stack is cooled), applying an interlayerbetween the two glass articles, and heating the three-layer stack(including the two pair sagged glass articles and interveninginterlayer) to create the laminate 50. The individual soda lime glass(SLG) glass articles in this laminate construction typically have athickness of about 1.6 mm or greater or about 2.1 mm or greater.

There is a trend toward using lightweight laminates glazing to improvefuel economy. New glazing designs consisting of a thicker outer glassarticle and a thin inner glass article. In one construction, the thickerglass article is SLG and the thinner glass article is a strengthenedglass article. The SLG articles can be annealed but not otherwisestrengthened to a level believed acceptable to compensate for strengthdegradation due to reduction in thickness. For example, even whenchemically strengthened, SLG articles do not exhibit sufficient strengthattributes (in terms of compressive stress and depth of compressivestress).

Thermal tempering is commonly used to strengthen thick, monolithic glassarticles and has the advantage of creating a deep compressive layer onthe glass surface, typically 21% of the overall glass thickness; howeverthe magnitude of the compressive stress is relatively low, typicallyless than 100 MPa. Furthermore, thermal tempering becomes increasinglyineffective for thin glass articles (i.e., glass articles having athickness of less than 2 mm). As such, standard thermal temperingprocess(es) are suitable for strengthening SLG articles having athickness of about 3 mm but not thin SLG articles. Moreover, SLGarticles have poor chemical strengthening characteristics.

Aluminosilicate glass articles are uniquely suited for use as thethinner glass article, especially those articles meeting in today'sglazing optical requirements. In particular, aluminosilicate glassescompositions that can be formed into very thin glass articles via downdraw processes (such as fusion forming processes). Moreover,aluminosilicate glass articles can be strengthened (in particular,chemical strengthened) to exhibit a wide range of compressive stresses(e.g., up to and even exceeding 1,000 MPa) and deep depths ofcompressive stress (e.g., up to and even exceeding 18% or 20% or thethickness of the glass articles).

Known aluminosilicate glasses tend to exhibit high viscosity relative toSLG articles at the SLG sag temperature (i.e., the temperature at whichSLG is typically sagged). Accordingly, this viscosity difference meansknown aluminosilicate glass articles must be sagged separately, as shownin FIG. 1B, and cannot be pair sagged, which adds cost to the overallmanufacturing process. In particular, FIG. 1B shows that when the glassarticles cannot be pair sagged, the method by which laminate glazing ismade includes an additional step of sagging the glass articlesseparately, instead of a single sagging step. Specifically, the methodincludes forming two glass articles 10A, 10B, cutting and finishing theglass articles 20A, 20B, heating each glass article to a sag temperatureto sag each glass article separately to the desired shape 30A, 30B. Useof the method of FIG. 1B could result in shape mismatch between the twoglass articles from the separate sagging steps. Further by using twoseparate sagging steps, twice as much energy and time is utilized.

Accordingly, there is a need for a thin glass article that can be pairsagged with another glass article that may differ in composition,strengthened to a sufficient degree, and is optionally, fusion-formed.

SUMMARY

This disclosure relates to glass compositions and glass articles havingsuch glass compositions, which can be pair sagged with different glassarticles (which include glass articles formed by a non-fusion processes,and glass articles made from SLG compositions). In some embodiments,glass compositions can be fusion formed or are fusion formable intoglass articles. In one or more embodiments, the glass articles can bestrengthened or are strengthened. Laminates that include such glassarticles and methods for forming such laminates are also disclosed.

A first aspect of this disclosure pertains to a glass article comprisinga glass composition that includes SiO₂ in an amount in a range fromabout 63 mol % to about 75 mol %, Al₂O₃ in an amount in a range fromabout 7 mol % to about 13 mol % (or from about 8 mol % to about 11 mol%), R₂O in an amount from about 13 mol % to about 24 mol %, and P₂O₅ inan amount in a range from about 0 mol % to about 3 mol %. Unlessotherwise specified, R₂O refers to the total amount of alkali metaloxides including Li₂O, Na₂O, K₂O, Rb₂O, and Cs₂O. In one or moreembodiments, the glass composition includes one or both of MgO and ZnO.When the glass composition includes MgO, it is present in an amount in arange from about 0 mol % to about 7 mol %. In some embodiments, MgO ispresent in an amount in a range from about 0 mol % to about 3 mol %.When the glass composition includes ZnO, it is present in an amount in arange from about 0 mol % to about 7 mol %. In some embodiments, ZnO ispresent in an amount in a range from about 0 mol % to about 5 mol %.

The glass composition of one or more embodiments may include Na₂O in anamount in a range from about 12 mol % to about 18 mol %. In one or moreembodiments, the glass composition includes K₂O in an amount in a rangefrom about 1 mol % to about 3.5 mol %. In some embodiments, the glasscomposition further comprises CaO in an amount in a range from about0.01 mol % to about 4 mol %. In some embodiments,

In one or more embodiments, the glass article comprises an anneal pointtemperature (° C.) and a softening point temperature (° C.), and therelationship of half the combination of anneal point temperature andsoftening point temperature ((anneal point temperature+softening pointtemperature)/2) is in a range from about 625° C. to about 725° C. Insome embodiments, the relationship of (anneal point+softening point)/2of the glass article equals less than about 700° C. In some embodiments,the glass article comprises a temperature (° C.) at a viscosity of 200poises (T₂₀₀) and a temperature (° C.) at a viscosity of 35000 poise(T₃₅₀₀₀), and wherein difference therebetween (T₂₀₀−T₃₅₀₀₀) has amagnitude in a range from about 400° C. to about 600° C. In one or moreembodiments, the glass article comprises a T₂₀₀, and wherein thedifference between the relationship (anneal point temperature+softeningpoint temperature)/2 and T₂₀₀ is less than −800° C. In some embodiments,the glass article comprises a T₃₅₀₀₀, and wherein the difference betweenthe relationship (anneal point temperature+softening pointtemperature)/2 and T₃₅₀₀₀ is less than −300° C. The glass articleaccording to one or more embodiments comprises a T₂₀₀ value, a T₃₅₀₀₀value, or T₂₀₀ and T₃₅₀₀₀ values that are greater than about 1030° C. Inone or more embodiments, the glass article may comprise a sagtemperature in a range from about 620° C. to about 720° C.

In one more embodiments, the glass article (or the glass compositionused to form the glass article) comprises a liquidus viscosity that isgreater than about 100 kiloPoise (kP). In some instances, the glassarticle (or the glass composition used to form the glass article)comprises a zircon breakdown viscosity that is less than about 35 kP.

The glass article of one or more embodiments may be strengthened. Insome instances, the glass article is fusion formed, as described herein.

A second aspect of this disclosure pertains to a glass article thatincludes a glass composition comprising Al₂O₃ in an amount greater than2 mol %, wherein the glass article comprises an anneal point temperature(° C.) and a softening point temperature (° C.), and the relationship of(anneal point temperature+softening point temperature)/2 is in a rangefrom about 625° C. to about 725° C. In some instances, the anneal pointtemperature may be less than about 580° C. In one or more embodiments,the glass article comprises a softening point temperature in a rangefrom about 725° C. and 860° C.

In one or more embodiments, the glass composition or the glass articlesformed from those compositions may comprise a T₃₅₀₀₀, of greater thanabout 1000° C. In one or more embodiments, the glass composition or theglass articles formed from those compositions may comprise a T₂₀₀ ofgreater than about 900° C. In one or more embodiments, the glasscomposition or the glass articles formed from those compositionscomprises a strain point temperature of less than about 530° C.

In one or more embodiments, the glass composition comprises an R₂Oamount that is equal to or greater than about 5 mol %. In someembodiments, the glass composition includes an R₂O amount in a rangefrom about 5 mol % to about 20 mol %.

In one or more embodiments, the glass composition may include a specificamount of RO. Unless otherwise specified, RO refers to the total amountof alkaline earth metal oxides such as MgO, CaO, SrO, BaO, ZnO and thelike. In one or more embodiments, the glass composition includes one orboth of MgO and ZnO. In one or more embodiments, the amount of MgO is ina range from about 0 mol % to about 7 mol %. In one or more embodiments,the amount of ZnO is in a range from about 0 mol % to about 7 mol %.

The glass composition or the glass articles formed from thosecompositions of one or more embodiments comprises a density of about 2.6g/cm³ or less. In some instances, the glass articles may bestrengthened. In some instances, the glass article is fusion formed.

A third aspect of this disclosure pertains to a vehicle comprising abody defining an interior and an opening in communication with theinterior; a glass article disposed in the opening. The glass articlecomprises a glass composition including Al₂O₃ in an amount greater than2 mol %, an anneal point temperature (° C.), and a softening pointtemperature (° C.), wherein the relationship of (anneal pointtemperature+softening point temperature)/2 is in a range from about 625°C. to about 725° C. The glass article (or composition used to form theglass article) may exhibit an anneal point temperature of less thanabout 600° C. In some instances, the glass article (or composition usedto form the glass article) further comprises a strain point temperatureof less than about 550° C. The glass article (or composition used toform the glass article) may comprise a sag temperature in a range fromabout 600° C. to about 700° C. The density of the glass article (orcomposition used to form the glass article) may be about 2.6 g/cm³ orless. In some embodiments, the glass article (or composition used toform the glass article) comprises a softening point in a range fromabout 725° C. and 860° C. In some embodiments, the glass articlecomprises a T₃₅₀₀₀ of greater than about 1000° C. In one or moreembodiments, the glass article further comprises a T₂₀₀ of greater thanabout 900° C.

In one or more embodiments, the glass article comprises a glasscomposition as otherwise described herein. For example, in someembodiments, the glass composition includes R₂O in an amount of about 16mol % or greater. In some instances, the glass composition comprises analkali metal oxide selected from Li₂O, Na₂O and K₂O, wherein such alkalimetal oxide is present in an amount greater than about 5 mol %. In someinstances, the glass composition comprises a total amount of amount ofalkali metal oxides which includes Li₂O, Na₂O, K₂O only, in a range fromabout 5 mol % to about 24 mol % or from about 17 mol % to about 24 mol%. The glass article may be strengthened in some embodiments. In someinstances the glass article is fusion formed.

A fourth aspect of this disclosure pertains to a laminate comprising: afirst glass layer, an interlayer disposed on the first glass layer, anda second glass layer disposed on the interlayer opposite the first glasslayer wherein either one or both the first glass layer and the secondglass layer comprises an embodiment of the glass articles describedherein. In one or more embodiments, either one of or both the firstglass layer and the second glass layer has a thickness less than about1.6 mm. In one or more embodiments, the first glass layer comprises anembodiment of the glass articles described herein, and has a thicknessof less than about 1.6 mm. In some particular embodiments, the secondglass layer comprises a thickness of 1.6 or greater. Optionally, thesecond glass layer differs compositionally from the first glass layer(e.g., the first glass layer comprises an embodiment of the glasscomposition described herein, and the second glass layer comprises SLG).

A fifth aspect of this disclosure pertains to laminate including a firstcurved glass layer comprising a first major surface, a second majorsurface opposing the first major surface, and a first thickness definedas the distance between the first major surface and second majorsurface, a second curved glass layer comprising a third major surface, afourth major surface opposing the third major surface, and a secondthickness defined as the distance between the third major surface andthe fourth major surface, and an interlayer disposed between the firstcurved glass layer and the second curved glass layer and adjacent thesecond major surface and third major surface.

In one or more embodiments, the first curved glass layer comprises afirst sag depth of about 2 mm or greater (e.g., from about 5 mm to about30 mm), and the second curved glass layer comprises a second sag depthof about 2 mm or greater (e.g., from about 5 mm to about 30 mm). In oneor more embodiments, the second surface forms a concave surface and thethird surface forms a concave surface, and vice versa.

In one or more embodiments, the first sag depth is within 10% of thesecond sag depth and a shape deviation between the first glass layer andthe second glass layer of ±5 mm or less (e.g., about ±1 mm or less, orabout ±0.5 mm or less), as measured by an optical three-dimensionalscanner.

The first glass layer comprises a first viscosity and the second glasslayer comprises a second viscosity. In one or more embodiments, thefirst viscosity at 630° C. is greater than the second viscosity at atemperature of 630° C. (e.g., at a temperature of about 630° C., thefirst viscosity is in a range from about 10 times the second viscosityto about 750 times the second viscosity).

In one or more embodiments, one of or both the first major surface andthe fourth major surface comprises an optical distortion of less than200 millidiopters (or about 100 millidiopters or less) as measured by anoptical distortion detector using transmission optics according to ASTM1561. In some embodiments, the third major surface or the fourth majorsurface comprises a membrane tensile stress of less than 7 MPa (e.g.,about 5 MPa or less or about 3 MPa or less) as measured by a surfacestressmeter, according to ASTM C1279.

In accordance with one or more embodiments, the first curved glass layercomprises the glass article described herein. The first thickness may beless than the second thickness. For example, the first thickness may befrom about 0.1 mm to less than about 1.6 mm, and the second thicknessmay be in a range from about 1.6 mm to about 3 mm.

The first curved glass layer may exhibit a sag temperature that differsfrom the second sag temperature. The magnitude of the difference betweenthe first sag temperature and the second sag temperature is in a rangefrom about 30° C. to about 150° C. In one or more embodiments, thelaminate is substantially free of visual distortion as measured by ASTMC1652/C1652M.

Optionally, the first curved glass layer is strengthened (e.g.,chemically strengthened, mechanically strengthened or thermallystrengthened). The second glass curved layer may be unstrengthened ormay be strengthened. In one or more embodiments, the second curved glasslayer comprises a soda lime silicate glass.

The first curved glass layer may have a first length and a first width,either one of or both the first length and the first width is about 0.25meters or greater. In one or more embodiments, the second curved glasslayer comprises a second length that is within 5% of the first length,and a second width that is within 5% of the first width. The laminatemay be simply curved (as defined herein) or complexly curved (as definedherein), and may optionally be an automotive glazing or architecturalglazing.

Another aspect pertains to a vehicle comprising: a body defining aninterior and an opening in communication with the interior; and thelaminate described herein disposed in the opening. Such laminate may becomplexly curved.

Unless otherwise specified, the glass compositions disclosed herein aredescribed in mole percent (mol %) as analyzed on an oxide basis.Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from that description or recognized by practicing theembodiments as described herein, including the detailed descriptionwhich follows, the claims, as well as the appended drawings.

A sixth aspect of this disclosure pertains to a method for forming alaminate. In one or more embodiments, the method includes stacking afirst glass article (which can comprise an embodiment of the glassarticles described herein), and a second glass article having adifferent composition from the first glass article to form a stack,placing the stack on a mold, heating the stack to a temperature greaterthan an annealing point temperature of the first glass article to form ashaped stack, and placing an interlayer between the first glass articleand the second glass layer.

In one or more embodiments, the first glass layer comprises a firstsurface and an second surface that opposes the first surface, and thesecond glass article comprises a third surface and a fourth surface thatopposes the third surface, and, in the stack, the second surface isadjacent to the third surface. In one or more embodiments, the secondsurface forms a concave surface and the third surface forms a concavesurface, and vice versa.

In one or embodiments, the shaped stack comprises a gap between thesecond surface and the third surface having a maximum distance of about10 mm or less (or about 5 mm or less, or about 3 mm or less).

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework to understanding the natureand character of the claims. The accompanying drawings are included toprovide a further understanding, and are incorporated in and constitutea part of this specification. The drawings illustrate one or moreembodiment(s), and together with the description serve to explainprinciples and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a process flow chart of a method of making a laminatedglazing using pair sagging according to one or more embodiments;

FIG. 1B is a process flow chart of a method of making laminated glazingaccording to the prior art;

FIG. 2 is a side view illustration of a glass article according to oneor more embodiments;

FIG. 3 is a side view illustration of a glass article according to oneor more embodiments;

FIG. 4 is a side view illustration of a laminate including a glassarticle according to one or more embodiments;

FIG. 5 is a side view illustration of a laminate including a glassarticle according to one or more embodiments;

FIG. 6 is a side view of a laminate including a glass article accordingto one or more embodiments;

FIG. 7 is an exploded side view of the glass article to be cold-formedto another glass article according to one or more embodiments;

FIG. 8 is a side view illustration of the resulting cold-formed laminateof FIG. 6;

FIG. 9 is an illustration of a vehicle including a glass article orlaminate according to one or more embodiments;

FIG. 10 is a graph showing the log viscosity curves of a known soda limesilicate glass, and Examples 63, 66 and 72 as a function of temperature.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings.

Aspects of this disclosure pertain to a glass article that can be pairsagged with another glass article that differs in any one or more ofcomposition, thickness, strengthen or strengthening level, and formingmethod (e.g., float formed as opposed to fusion formed). In one or moreembodiments, the glass article can be fusion formed or is fusionformable, meaning it is or can be formed using a fusion process.

In most cases automotive glazing is curved or bent, and is not flat orplanar. Architectural applications may also use similarly curved glassarticles. Depending on thicknesses of the glass articles and the desiredshape, the glass articles may be cold-formed (without using heat) orthermally shaped (without heat) to achieve the curved shape.

Thermal shaping can include a sagging process, which uses gravity toshape the glass when it is heated. In the sagging step, a glass articleis placed on top of another glass article forming a stack (with apotential intervening release layer), which is placed on a mold. Thestack and mold are both heated by placing in a furnace (e.g., a boxfurnace, or a lehr furnace) in which the stack is gradually heated tothe sag temperature of the glass articles. During this process, gravitysags the glass articles together to a curved shape.

The heating time and temperature are selected to obtain the desireddegree of sagging and final shape. Subsequently, the glass articles areremoved from the furnace and cooled. The two glass articles are thenseparated, re-assembled with an interlayer between the glass articlesand heated under vacuum to seal the glass articles and interlayertogether into a laminate.

Sagging the two glass articles together as shown in step 40 of FIG. 1Astreamlines the manufacturing process; however, when the glass articleshave different sag temperatures, pair sagging becomes a challenge. Forexample, known aluminosilicate glasses have a sag temperature that ismore than 80° C. greater than the sag temperature of SLG. Moreover,known aluminosilicate glasses have viscosities that are more than 200times greater than the viscosity of typical SLG at their respective sagtemperatures.

A first aspect of this disclosure pertains to a glass article that canbe pair sagged with another glass article that differs in any one ormore of composition, thickness, strengthening level, and forming method(e.g., float formed as opposed to fusion formed). In particular, theembodiments of the glass article can be pair sagged with SLG or otherglass articles with lower sag temperatures than known aluminosilicateglass articles, even when at reduced thicknesses (e.g., less than 2.1 mmor less than 1.6 mm). In addition, such glass articles retain theirfusion formability and strengthening capability. In one or moreembodiments, the glass article includes a glass composition comprisingSiO₂ in an amount in a range from about 63 mol % to about 75 mol %,Al₂O₃ in an amount in a range from about 7 mol % to about 13 mol %, R₂Oin an amount from about 13 mol % to about 24 mol % (or about 18 mol % toabout 24 mol %), P₂O₅ in an amount in a range from about 0 mol % toabout 3 mol %. In one or more embodiments, the glass composition caninclude one or both of MgO and ZnO. When MgO is included in the glasscomposition, the amount MgO present is in a range from about 0 mol % toabout 7 mol %. When ZnO is included in the glass composition, the amountof ZnO present is in a range from about 0 mol % to about 7 mol %. In oneor more embodiments, the glass article (or glass composition used toform the glass article) exhibits an anneal point temperature (° C.) anda softening point temperature (° C.), and the relationship of (annealpoint temperature+softening point temperature)/2 is in a range fromabout 625° C. to about 725° C. or from about 650° C. to about 690° C.

In one or more embodiments, the glass article is described as analuminosilicate glass article or including an aluminosilicate glasscomposition. In such embodiments, the aluminosilicate glass compositionor glass article formed therefrom includes SiO₂ and Al₂O₃ and is notSLG. In this regard, the glass composition or article formed therefromincludes Al₂O₃ in an amount of about 2 mol % or greater, 2.25 mol % orgreater, 2.5 mol % or greater, about 2.75 mol % or greater, about 3 mol% or greater.

In one or more embodiments, the glass composition includes Al₂O₃ in anamount greater than about 2 mol %, greater than about 5 mol %, orgreater than about 6 mol %. In one or more embodiments, the glasscomposition includes Al₂O₃ in a range from greater than about 7 mol % toabout 13 mol %, from greater than about 8 mol % to about 13 mol %, fromabout 9 mol % to about 13 mol %, from about 9 mol % to about 13 mol %,from about 10 mol % to about 13 mol %, from about 7 mol % to about 12mol %, from 7 mol % to about 11 mol %, from about7 mol % to about 10 mol%, from about 7 mol % to about 9 mol %, from about 8 mol % to about 12mol %, from about 8 mol % to about 11 mol %, from about 8 mol % to about10 mol %, or from about 9 mol % to about 10 mol %, and all ranges andsub-ranges therebetween.

In one or more embodiments, the glass composition includes SiO₂ in anamount in the range from about 63 mol % to about 75 mol %, from about 64mol % to about 75 mol %, from about 65 mol % to about 75 mol %, fromabout 66 mol % to about 75 mol %, from about 68 mol % to about 75 mol %,from about 70 mol % to about 75 mol %, from about 72 mol % to about 75mol %, f from about 63 mol % to about 74 mol %, from about 63 mol % toabout 72 mol %, from about 63 mol % to about 70 mol %, from about 63 mol% to about 68 mol %, from about 63 mol % to about 66 mol %, from about63 mol % to about 67 mol %, from about 64 mol % to about 76 mol %, orfrom about 65 mol % to about 66 mol %, and all ranges and sub-rangestherebetween.

In one or more embodiments, the glass composition may include a totalamount of R₂O that is greater than or equal to about 5 mol %, greaterthan or equal to about 10 mol %, or greater than or equal to about 12mol %. In some embodiments, the glass composition includes a totalamount of R₂O in a range from 5 mol % to about 24 mol %, from about 6mol % to about 24 mol %, from about 8 mol % to about 24 mol %, fromabout 10 mol % to about 24 mol %, from about 12 mol % to about 24 mol %,from 13 mol % to about 24 mol %, from 14 mol % to about 24 mol %, from15 mol % to about 24 mol %, from 16 mol % to about 24 mol %, from about17 mol % to about24 mol %, from 18 mol % to about24 mol %, from about 20mol % to about 24 mol %, from about 13 mol % to about 22 mol %, fromabout 13 mol % to about 20 mol %, from about 13 mol % to about 18 mol %,from about 13 mol % to about 16 mol %, 13 mol % to about 15 mol %, from17 mol % to about 21 mol %, from 18 mol % to about 20 mol %, or from 19mol % to about 21 mol %, and all ranges and sub-ranges therebetween. Inone or more embodiments, the glass composition may be substantially freeof Rb₂O, Cs₂O or both Rb₂O and Cs₂O. As used herein, the phrase“substantially free” with respect to the components of the compositionmeans that the component is not actively or intentionally added to thecomposition during initial batching, but may be present as an impurityin an amount less than about 0.001 mol %. In one or more embodiments,the glass composition may include R₂O, which may include the totalamount of Li₂O, Na₂O and K₂O only (i.e., the glass composition issubstantially free of Rb₂O and Cs₂O). In one or more embodiments, theglass composition may include R₂O, which may include the total amount ofNa₂O and K₂O only (i.e., the glass composition is substantially free ofLi₂O, Rb₂O and Cs₂O). In one or more embodiments, the glass compositionmay comprise at least one alkali metal oxide selected from Li₂O, Na₂Oand K₂O, wherein the alkali metal oxide is present in an amount greaterthan about 5 mol %, greater than about 8 mol %, greater than about 10mol %, or greater than about 12 mol %. In such embodiments, the glasscomposition or glass article formed therefrom may be characterized as analkali aluminosilicate glass due to the presence of an alkali metaloxide.

In one or more embodiments, the glass composition comprises Na₂O in anamount greater than or equal to about 10 mol %, greater than or equal toabout 11 mol %, greater than or equal to about 12 mol %, or greater thanor equal to about 14 mol %. In one or more embodiments, the compositionincludes Na₂O in a range from about from about 12 mol % to about 20 mol%, from about 14 mol % to about 20 mol %, from about 15 mol % to about20 mol %, from about 16 mol % to about 20 mol %, from about 18 mol % toabout 20 mol %, from about 12 mol % to about 18 mol %, from about 12 mol% to about 16 mol %, from about 12 mol % to about 14 mol %, from about14 mol % to about 18 mol %, from about 15 mol % to about 18 mol %, fromabout 16 mol % to about 18 mol %, or from about 16 mol % to about 17 mol%, and all ranges and sub-ranges therebetween.

In one or more embodiments, the glass composition includes less thanabout 4 mol % K₂O, or less than about 3 mol % K₂O. In some instances,the glass composition may include K₂O in an amount in a range from aboutfrom about 0.5 mol % to about 4 mol %, from about 0.5 mol % to about 3.5mol %, from about 0.5 mol % to about 3 mol %, from about 0.5 mol % toabout 2.5 mol %, from about 0.5 mol % to about 2 mol %, from about 0.5mol % to about 1.5 mol %, from about 0.5 mol % to about 1 mol %, fromabout 1 mol % to about 4 mol %, from about 1 mol % to about 3.5 mol %,from about 1 mol % to about 3 mol %, from about 1 mol % to about 2.5 mol%, from about 1.5 mol % to about 4 mol %, from about 1.5 mol % to about3.5 mol %, from about 1.5 mol % to about 3 mol %, from about 1.5 mol %to about 2.5 mol %, from about 1.75 mol % to about 3 mol %, from about1.75 mol % to about 2.75 mol %, from about 1.75 mol % to about 3 mol %,or from about 2 mol % to about 3 mol %, and all ranges and sub-rangestherebetween.

In one or more embodiments, the composition includes Li₂O in a rangefrom about 0 mol % to about 4 mol %, from about 0 mol % to about 3.5 mol%, from about 0 mol % to about 3 mol %, from about 0 mol % to about 2.5mol %, from about 0 mol % to about 2 mol %, from about 0 mol % to about1.5 mol %, from about 0 mol % to about 1 mol %, from about 0.1 mol % toabout 4 mol %, from about 0.1 mol % to about 3.5 mol %, from about 0.1mol % to about 3 mol %, from about 0.1 mol % to about 2.5 mol %, fromabout 0.1 mol % to about 2 mol %, from about 0.1 mol % to about 1.5 mol%, from about 0.1 mol % to about 1 mol %, from about 1 mol % to about 4mol %, from about 1 mol % to about 3.5 mol %, from about 1 mol % toabout 3 mol %, from about 1 mol % to about 2.5 mol %, from about 1 mol %to about 2 mol %, or from about 1 mol % to about 1.5 mol %, and allranges and sub-ranges therebetween. In one or more embodiments, theglass composition is substantially free of Li₂O.

In one or more embodiments, the amount of Na₂O in the composition may begreater than the amount of Li₂O. In some instances, the amount of Na₂Omay be greater than the combined amount of Li₂O and K₂O.

In one or more embodiments, the glass composition comprises thecomposition relationship of a difference between R₂O and the amount ofAl₂O₃ (i.e., R₂O—Al₂O₃) that is in a range from about 4 mol % to about12 mol %, from about 5 mol % to about 12 mol %, from about 6 mol % toabout 12 mol %, from about 7 mol % to about 12 mol %, from about 8 mol %to about 12 mol %, from about 9 mol % to about 12 mol %, from about 4mol % to about 11 mol %, from about 4 mol % to about 10 mol %, fromabout 4 mol % to about 9 mol %, from about 4 mol % to about 8 mol %,from about 4 mol % to about 7 mol %, or from about 8 mol % to about 10mol %, and all ranges and sub-ranges therebetween.

In one or more embodiments, the glass composition comprises thecompositional ratio of R₂O to Al₂O₃ (i.e., R₂O:Al₂O₃) that is about 3 orless, about 2.5 or less, or about 2 or less. In some embodiments, theglass composition comprises the compositional ratio R₂O:Al₂O₃ in therange from about 1.5 to about 3. In some embodiments, the glasscomposition comprises the compositional ratio R₂O:Al₂O₃ in a range fromabout 1.6 to about 3, from about 1.7 to about 3, from about 1.8 to about3, from about 1.9 to about 3, from about 2 to about 3, from about 2.1 toabout 3, from about 2.2 to about 3, from about 2.3 to about 3, fromabout 2.4 to about 3, from about 2.5 to about 3, from about 1.5 to about2.9, from about 1.5 to about 2.8, from about 1.5 to about 2.6, fromabout 1.5 to about 2.5, from about 1.5 to about 2.4, from about 1.5 toabout 2.2, from about 1.5 to about 2, from about 1.5 to about 1.9, orfrom about 1.5 to about 1.8, and all ranges and sub-ranges therebetween.

In one or more embodiments, the glass composition comprises B₂O₃ (e.g.,about 0.01 mol % or greater). In some embodiments, the glass compositionmay be substantially free of B₂O₃. In one or more embodiments, the glasscomposition comprises B₂O₃ in an amount in a range from about 0 mol % toabout 2 mol %, from about 0 mol % to about 1.9 mol %, from about 0 mol %to about 1.8 mol %, from about 0 mol % to about 1.6 mol %, from about 0mol % to about 1.5 mol %, from about 0 mol % to about 1.4 mol %, fromabout 0 mol % to about 1.3 mol %, from about 0 mol % to about 1.2 mol %,from about 0 mol % to about 1.1 mol %, from about 0 mol % to about 1 mol%, from about 0.5 mol % to about 2.5 mol %, from about 0.5 mol % toabout 2 mol %, or from about 0.5 mol % to about 1.5 mol %, and allranges and sub-ranges therebetween.

In one or more embodiments, the glass composition comprises P₂O₅ (e.g.,about 0.01 mol % or greater). In some embodiments, the glass compositionmay be substantially free of P₂O₅. In one or more embodiments, the glasscomposition comprises P₂O₅ in an amount in a range from about 0 mol % toabout 3 mol %, from about 0 mol % to about 2.9 mol %, from about 0 mol %to about 2.8 mol %, from about 0 mol % to about 2.6 mol %, from about 0mol % to about 2.5 mol %, from about 0 mol % to about 2.4 mol %, fromabout 0 mol % to about 2.3 mol %, from about 0 mol % to about 2.2 mol %,from about 0 mol % to about 2.1 mol %, from about 0 mol % to about 2 mol%, from about 0.5 mol % to about 3 mol %, from about 0.5 mol % to about2.5 mol %, from about 0.5 mol % to about 2 mol %, from about 0.5 mol %to about 1.5 mol %, from about 0.5 mol % to about 1 mol %, from about1.5 mol % to about 3 mol %, or from about 2 mol % to about 3 mol %, andall ranges and sub-ranges therebetween.

In one or more embodiments, the glass composition may include a totalamount of RO in a range from about 0 mol % to about 18 mol %. In someembodiments, the glass composition includes a non-zero amount of RO upto about 18 mol %. In one or more embodiments, the glass compositioncomprises RO in an amount from about 0 mol % to about 16 mol %, fromabout 0 mol % to about 15 mol %, from about 0 mol % to about 14 mol %,from about 0 mol % to about 12 mol %, from about 0 mol % to about 11 mol%, from about 0 mol % to about 10 mol %, from about 0 mol % to about 9mol %, from about 0 mol % to about 8 mol %, from about 0.1 mol % toabout 18 mol %, from about 0.1 mol % to about 16 mol %, from about 0.1mol % to about 15 mol %, from about 0.1 mol % to about 14 mol %, fromabout 0.1 mol % to about 12 mol %, from about 0.1 mol % to about 11 mol%, from about 0.1 mol % to about 10 mol %, from about 0.1 mol % to about9 mol %, or from about 0.1 mol % to about 8 mol %, and all ranges andsub-ranges therebetween.

In one or more embodiments, the glass composition includes CaO in anamount about 5 mol % or less, about 4.5 mol % or less, about 4 mol % orless, about 3.5 mol % or less, about 3 mol % or less, about 2.5 mol % orless, about 2 mol % or less, about 1.5 mol % or less, or about 1 mol %or less. In one or more embodiments, the glass composition issubstantially free of CaO. In one or more embodiments, the glasscomposition comprises CaO in an amount from about 0 mol % to about 5 mol%, from about 0 mol % to about 4.5 mol %, from about 0 mol % to about 4mol %, from about 0 mol % to about 3.5 mol %, from about 0 mol % toabout 3 mol %, from about 0 mol % to about 2.5 mol %, from about 0 mol %to about 2 mol %, from about 0 mol % to about 1.5 mol %, from about 0mol % to about 1 mol %, from about 0 mol % to about 0.8 mol %, fromabout 0 mol % to about 0.75 mol %, from about 0 mol % to about 0.5 mol%, from about 0 mol % to about 0.25 mol %, from about 0 mol % to about0.1 mol %, from about 0.01 mol % to about 5 mol %, from about 0.01 mol %to about 4.5 mol %, from about 0.01 mol % to about 4 mol %, from about0.01 mol % to about 3.5 mol %, from about 0.01 mol % to about 3 mol %,from about 0.01 mol % to about 2.5 mol %, from about 0.01 mol % to about2 mol %, from about 0.01 mol % to about 1.5 mol %, from about 0.01 mol %to about 1 mol %, from about 0.01 mol % to about 0.8 mol %, from about0.01 mol % to about 0.75 mol %, from about 0.01 mol % to about 0.5 mol%, from about 0.01 mol % to about 0.25 mol %, or from about 0.01 mol %to about 0.1 mol %, and all ranges and sub-ranges therebetween.

In some embodiments, the glass composition comprises MgO in an amount inthe range from about 0 mol % to about 7 mol %, from about 0 mol % toabout 6.5 mol %, from about 0 mol % to about 6 mol %, from about 0 mol %to about 5.5 mol %, from about 0 mol % to about 5 mol %, from about 0mol % to about 4.5 mol %, from about 0 mol % to about 4 mol %, fromabout 0 mol % to about 3.5 mol %, from about 0 mol % to about 3 mol %,from about 0 mol % to about 2.5 mol %, from about 0 mol % to about 2 mol%, from about 0 mol % to about 1.5 mol %, from about 0 mol % to about 1mol %, from about 0.5 mol % to about 6.5 mol %, from about 1 mol % toabout 6.5 mol %, from about 1.5 mol % to about 6.5 mol %, from about 2mol % to about 6.5 mol %, from about 2.5 mol % to about 6.5 mol %, fromabout 3 mol % to about 6.5 mol %, from about 3.5 mol % to about 6.5 mol%, from about 4 mol % to about 6.5 mol %, from about 4.5 mol % to about6.5 mol %, from about 5 mol % to about 6.5 mol %, from about 0.5 mol %to about 3.5 mol %, from about 1 mol % to about 3.5 mol %, from about1.5 mol % to about 3 mol %, from about 0.5 mol % to about 2.5 mol %, orfrom about 2 mol % to about 4 mol %, and all ranges and sub-rangestherebetween.

In some embodiments, the glass composition comprises ZnO in an amount inthe range from about 0 mol % to about 7 mol %, from about 0 mol % toabout 7.5 mol %, from about 0 mol % to about 6 mol %, from about 0 mol %to about 5.5 mol %, from about 0 mol % to about 5 mol %, from about 0mol % to about 4.5 mol %, from about 0 mol % to about 4 mol %, fromabout 0 mol % to about 3.5 mol %, from about 0 mol % to about 3 mol %,from about 0 mol % to about 2.5 mol %, from about 0 mol % to about 2 mol%, from about 0 mol % to about 1.5 mol %, from about 0 mol % to about 1mol %, from about 0.5 mol % to about 7 mol %, from about 0.5 mol % toabout 6.5 mol %, from about 0.5 mol % to about 6 mol %, from about 0.5mol % to about 5.5 mol %, from about 0.5 mol % to about 5 mol %, fromabout 0.5 mol % to about 4.5 mol %, from about 1 mol % to about 7 mol %,from about 1 mol % to about 6.5 mol %, from about 1 mol % to about 6 mol%, from about 1 mol % to about 5.5 mol %, from about 1 mol % to about 5mol %, from about 1 mol % to about 4.5 mol %, from about 1.5 mol % toabout 4.5 mol %, from about 2 mol % to about 4.5 mol %, from about 2.5mol % to about 4.5 mol %, from about 3 mol % to about 4.5 mol %, fromabout 3.5 mol % to about 4.5 mol %, from about 0.5 mol % to about 3.5mol %, from about 1 mol % to about 3.5 mol %, from about 1.5 mol % toabout 4 mol %, or from about 2 mol % to about 3.5 mol %, and all rangesand sub-ranges therebetween.

In some embodiments, the glass composition comprises SrO in an amount inthe range from about 0 mol % to about 2 mol %, from about 0 mol % toabout 1.5 mol %, from about 0 mol % to about 1 mol %, from about 0.5 mol% to about 2 mol %, from about 1 mol % to about 2 mol %, or from about1.5 mol % to about 2 mol %, and all ranges and sub-ranges therebetween.

In some embodiments, the glass composition comprises BaO in an amount inthe range from about 0 mol % to about 2 mol %, from about 0 mol % toabout 1.5 mol %, from about 0 mol % to about 1 mol %, from about 0.5 mol% to about 2 mol %, from about 1 mol % to about 2 mol %, or from about1.5 mol % to about 2 mol %, and all ranges and sub-ranges therebetween.

In one or more embodiments, the glass composition comprises SnO₂ in anamount equal to or less than about 0.25 mol %, less than about 0.24 mol%, less than about 0.22 mol %, less than about 0.2 mol %, less thanabout 0.18 mol %, less than about 0.16 mol %, less than about 0.15 mol%, less than about 0.14 mol %, less than about 0.12 mol %. In one ormore embodiments, the glass composition comprises SnO2 in a range fromabout 0.01 mol % to about 0.25 mol %, from about 0.01 mol % to about0.24 mol %, from about 0.01 mol % to about 0.22 mol %, from about 0.01mol % to about 0.2 mol %, from about 0.01 mol % to about 0.18 mol %,from about 0.01 mol % to about 0.16 mol %, from about 0.01 mol % toabout 0.15 mol %, from about 0.01 mol % to about 0.14 mol %, from about0.01 mol % to about 0.12 mol %, or from about 0.01 mol % to about 0.10mol %, and all ranges and sub-ranges therebetween. In some embodiments,SnO₂ may be substituted with another fining agent is a multivalent orother oxygen absorbing agent such as antimony, arsenic, iron, cerium,and the like.

In one or more embodiments, the glass composition may include an oxidethat imparts a color or tint to the glass articles. In some embodiments,the glass composition includes an oxide that prevents discoloration ofthe glass article when the glass article is exposed to ultravioletradiation. Examples of such oxides include, without limitation oxidesof: Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ce, W, and Mo.

In one or more embodiments, the glass composition includes Fe expressedas Fe₂O₃, wherein Fe is present in an amount up to (and including) about1 mol %. In some embodiments, the glass composition is substantiallyfree of Fe. In one or more embodiments, the glass composition comprisesFe expressed as Fe₂O₃ in a range from about 0 mol % to about 1 mol %,from about 0 mol % to about 0.9 mol %, from about 0 mol % to about 0.8mol %, from about 0 mol % to about 0.7 mol %, from about 0 mol % toabout 0.6 mol %, from about 0 mol % to about 0.5 mol %, from about 0 mol% to about 0.4 mol %, from about 0 mol % to about 0.3 mol %, from about0 mol % to about 0.2 mol %, 0 mol % to about 0.1 mol %, from about 0.01mol % to about 0.9 mol %, from about 0.01 mol % to about 0.8 mol %, fromabout 0.01 mol % to about 0.7 mol %, from about 0.01 mol % to about 0.6mol %, from about 0.01 mol % to about 0.5 mol %, from about 0.01 mol %to about 0.4 mol %, from about 0.01 mol % to about 0.3 mol %, from about0.01 mol % to about 0.2 mol %, from about 0.05 mol % to about 0.1 mol %,from about 0.1 mol % to about 1 mol %, from about 0.2 mol % to about 1mol %, from about 0.3 mol % to about 1 mol %, from about 0.4 mol % toabout 1 mol %, from about 0.5 mol % to about 1 mol %, from about 0.6 mol% to about 1 mol %, from about 0.2 mol % to about 0.8 mol %, or fromabout 0.4 to about 0.8 mol % and all ranges and sub-ranges therebetween.In one or more embodiments, the Fe source may be oxalate/I2, Fe₂O₃/I8.In some embodiments, the about of Fe expressed as Fe₂O₃ is expressed inweight % in a range from about 0.1 weight % to about 5 weight %, fromabout 0.1 weight % to about 4 weight %, from about 0.1 weight % to about3 weight %, from about 0.1 weight % to about 2.5 weight %, from about0.2 weight % to about 5 weight %, from about 0.3 weight % to about 5weight %, or from about 0.4 weight % to about 5 weight %, and all rangesand sub-ranges therebetween.

In one or more embodiments, the glass composition comprises a totalamount of Co, expressed as Co₃O₄, in an amount in the range from about0.001 mol % to 0.01 mol %, from about 0.002 mol % to 0.01 mol %, fromabout 0.003 mol % to 0.01 mol %, from about 0.004 mol % to 0.01 mol %,from about 0.005 mol % to 0.01 mol %, from about 0.006 mol % to 0.01 mol%, from about 0.007 mol % to 0.01 mol %, from about 0.001 mol % to 0.009mol %, from about 0.001 mol % to 0.008 mol %, from about 0.001 mol % to0.007 mol %, from about 0.001 mol % to 0.006 mol %, or from about 0.001mol % to 0.005 mol %, and all ranges and sub-ranges therebetween.

The glass composition of one or more embodiments may include any one ormore of NiO, V₂O₅, and TiO₂.

Where the glass composition includes TiO₂, TiO₂ may be present in anamount of about 5 mol % or less, about 2.5 mol % or less, about 2 mol %or less or about 1 mol % or less. In one or more embodiments, the glasscomposition may be substantially free of TiO₂. Where the glasscomposition includes NiO, NiO may be present in an amount of about 0.6mol % or less, or about 0.1 mol % or less. In one or more embodiments,the glass composition may be substantially free of NiO. In one or moreembodiments, the glass composition may be substantially free of V₂O₅. Inone or more embodiments, the glass composition may be substantially freeof TiO₂. In one or more embodiments, the glass composition may besubstantially free of any two or all three of NiO, V₂O₅, and TiO₂.

In one or more embodiments, the glass composition may include less thanabout 0.9 mol % CuO (e.g., less than about 0.5 mol %, less than about0.1 mol %, or less than about 0.01 mol %). In some embodiments, theglass composition is substantially free of CuO.

In one or more embodiments, the glass composition may include less thanabout 0.2 mol % Se (e.g., less than about 0.1 mol %, or less than about0.01 mol %). In some embodiments, the glass composition is substantiallyfree of Se.

In one or more embodiments, the glass composition (or article formedtherefrom) comprises a liquidus viscosity that enables the formation ofthe glass articles via specific techniques. As used herein, the term“liquidus viscosity” refers to the viscosity of a molten glass at theliquidus temperature, wherein the term “liquidus temperature” refers tothe temperature at which crystals first appear as a molten glass coolsdown from the melting temperature (or the temperature at which the verylast crystals melt away as temperature is increased from roomtemperature).

In one or more embodiments, the glass composition (or the glass articleformed therefrom) exhibits a liquidus viscosity greater than or equal toabout 100 kiloPoise (kP), greater than or equal to about 500 kP, greaterthan or equal to about 1000 kP, greater than or equal to 5000 kP,greater than or equal to 10,000 kP, greater than or equal to 15,000 kP,greater than or equal to 20,000 kP, greater than or equal to 25,000 kP,greater than or equal to 30,000 kP, greater than or equal to 35,000 kP.In one or more embodiments, the glass composition (or glass articleformed therefrom) exhibits a liquidus viscosity in the range from about100 kP to about 50,000 kP. Such glass compositions can be described asfusion formable and the resulting glass articles formed by a fusionprocess are characterized as fusion formed, where fusion formable andfusion formed indicate the liquidus viscosity exhibited by the glasscomposition or glass article, respectively. In some embodiments, thefusion formed glass article is substantially free of draw lines that arepresent in typical float formed glass articles. The liquidus viscosityis determined by the following method. First the liquidus temperature ofthe glass is measured in accordance with ASTM C829-81 (2015), titled“Standard Practice for Measurement of Liquidus Temperature of Glass bythe Gradient Furnace Method”. Next the viscosity of the glass at theliquidus temperature is measured in accordance with ASTM C965-96 (2012),titled “Standard Practice for Measuring Viscosity of Glass Above theSoftening Point”.

The various embodiments of the glass articles described herein haveglass compositions that exhibit one or more of relatively low annealpoint temperature, softening point temperature, sag temperature andrelatively high liquidus viscosities.

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a strain point temperature in arange from about 475° C. to about 575° C. In one or more embodiments,the strain point temperature is in a range from about 480° C. to about575° C., from about 490° C. to about 575° C., from about 500° C. toabout 575° C., from about 510° C. to about 575° C., from about 520° C.to about 575° C., from about 530° C. to about 575° C., from about 540°C. to about 575° C., from about 550° C. to about 575° C., from about475° C. to about 570° C., from about 475° C. to about 560° C., fromabout 475° C. to about 550° C., from about 475° C. to about 540° C.,from about 475° C. to about 530° C., from about 475° C. to about 520°C., from about 475° C. to about 510° C., or from about 475° C. to about500° C., and all ranges and sub-ranges therebetween. In some instances,the glass composition or glass articles formed from those compositionsexhibit a strain point temperature that is less than about 550° C. orless, or about 530° C. or less. The strain point temperature isdetermined using the beam bending viscosity method of ASTM C598-93(2013).

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit an annealing point temperature ina range from about 510° C. to about 610° C. In one or more embodiments,the glass composition or glass articles formed from those compositionsexhibit an annealing point temperature that is less than about 580° C.The annealing point may be in a range from about 520° C. to about 610°C., from about 530° C. to about 610° C., from about 540° C. to about610° C., from about 550° C. to about 610° C., from about 560° C. toabout 610° C., from about 510° C. to about 600° C., from about 510° C.to about 590° C., from about 510° C. to about 580° C., from about 510°C. to about 570° C., from about 510° C. to about 560° C., from about510° C. to about 550° C., from about 510° C. to about 540° C., or fromabout 530° C. to about 570° C., and all ranges and sub-rangestherebetween. In some embodiments, the anneal point temperature is lessthan about 600° C. The annealing point is determined using the beambending viscosity method of ASTM C598-93 (2013).

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a softening point temperature ina range from about 725° C. and 860° C. The softening point temperaturemay be in a range from about 730° C. to about 860° C., from about 740°C. to about 860° C., from about 750° C. to about 860° C., from about760° C. to about 860° C., from about 770° C. to about 860° C., fromabout 780° C. to about 860° C., from about 790° C. to about 860° C.,from about 800° C. to about 860° C., from about 725° C. and 850° C.,from about 725° C. and 840° C., from about 725° C. and 830° C., fromabout 725° C. and 820° C., from about 725° C. and 810° C., from about725° C. and 800° C., from about 725° C. and 790° C., from about 725° C.and 780° C., from about 725° C. and 770° C., from about 725° C. and 760°C., or from about 725° C. and 750° C., and all ranges and sub-rangestherebetween. The softening point temperature is determined using theparallel plate viscosity method of ASTM C1351M-96 (2012).

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a difference in magnitude betweenthe annealing point temperature and the softening point temperature thatis greater than about 150° C., greater than about 175° C., greater thanabout 200° C., or greater than about 225° C. In some embodiments, thedifference in magnitude between the annealing point temperature and thesoftening point temperature is in a range from about 175° C. to about250° C., from about 180° C. to about 250° C., from about 190° C. toabout 250° C., from about 200° C. to about 250° C., from about 210° C.to about 250° C., from about 220° C. to about 250° C., from about 225°C. to about 250° C., from about 175° C. to about 240° C., from about175° C. to about 230° C., from about 175° C. to about 220° C., fromabout 175° C. to about 210° C., from about 175° C. to about 200° C.,from about 175° C. to about 190° C., or from about 200° C. to about 240°C.

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a relationship of (anneal pointtemperature+softening point temperature)/2 that is less than about 720°C. For example, the relationship (anneal point temperature+softeningpoint temperature)/2 may be about 710° C. or less, about 700° C. orless, about 690° C. or less, about 680° C. or less, about 670° C. orless, about 660° C. or less, about 650° C. or less. In some instances,the relationship (anneal point temperature+softening pointtemperature)/2 is in a range from about 625° C. to about 725° C., fromabout 625° C. to about 700° C., from about 650° C. to about 700° C. orfrom about 675° C. to about 700° C. In some embodiments, the glasscomposting or glass articles formed therefrom exhibit the describedrelationship of (anneal point temperature+softening pointtemperature)/2, while also being characterized as an aluminosilicateglass. In one or more particular embodiments, the glass composition orglass articles formed therefrom exhibit the described relationship of(anneal point temperature+softening point temperature)/2 while alsoincluding more than about 2 mol % Al₂O₃ (e.g., 2.25 mol % or greater,2.5 mol % or greater, or about 3 mol % or greater).

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a T₂₀₀ that is greater than about900° C. or greater than about 1200° C., as measured by Fulcher fit tohigh temperature viscosity (HTV) data (i.e., all the temperaturemeasurements from 100 kP to 100 poise). For example, the glasscomposition or glass articles formed from those compositions may exhibita T₂₀₀ in a range from about 900° C. to about 1800° C., from about 1000°C. to about 1800° C., from about 1100° C. to about 1800° C., from about1200° C. to about 1800° C., from about 1300° C. to about 1800° C., fromabout 1400° C. to about 1800° C., from about 1500° C. to about 1800° C.,from about 900° C. to about 1700° C., from about 900° C. to about 1600°C., from about 900° C. to about 1500° C., from about 900° C. to about1400° C., from about 900° C. to about 1300° C., from about 900° C. toabout 1200° C., from about 900° C. to about 1100° C., from about 1200°C. to about 1700° C., from about 1200° C. to about 1600° C., from about1200° C. to about 1500° C., from about 1200° C. to about 1400° C., orfrom about 1500° C. to about 1700° C.

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a T₃₅₀₀₀ that is greater thanabout 1000° C., as measured by Fulcher fit to high temperature viscosity(HTV) data (i.e., all the temperature measurements from 100 kP to 100poise). In some embodiments, the glass composition or glass articlesformed from those compositions exhibit a T₃₅₀₀₀ about 1000° C. orgreater, 1010° C. or greater, about 1020° C. or greater, about 1030° C.or greater, about 1040° C. or greater, about 1050° C. or greater, about1060° C. or greater, about 1070° C. or greater, about 1080° C. orgreater, about 1090° C. or greater, about 1100° C. or greater, about1110° C. or greater, about 1120° C. or greater, about 1130° C. orgreater, about 1140° C. or greater, about 1150° C. or greater, about1160° C. or greater, about 1170° C. or greater, about 1180° C. orgreater, about 1190° C. or greater, about 1200° C. or greater, about1210° C. or greater, about 1220° C. or greater, about 1230° C. orgreater, about 1240° C. or greater, or about 1250° C. or greater. TheT₃₅₀₀₀ may be in a range from about 1000° C. to about 1200° C., fromabout 1010° C. to about 1200° C., from about 1020° C. to about 1200° C.,from about 1030° C. to about 1200° C., from about 1040° C. to about1200° C., from about 1050° C. to about 1200° C., from about 1000° C. toabout 1190° C., from about 1000° C. to about 1180° C., from about 1000°C. to about 1170° C., from about 1000° C. to about 1160° C., from about1000° C. to about 1150° C., or from about 1000° C. to about 1140° C.

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a temperature at a viscosity ofabout 200 kP (T₂₀₀₀₀₀) that is greater than about 900° C., as measuredby Fulcher fit to HTV data. In some embodiments, the glass compositionor glass articles formed from those compositions exhibit a T₂₀₀₀₀₀ thatis about 910° C. or greater, 920° C. or greater, 930° C. or greater,940° C. or greater, 950° C. or greater, 960° C. or greater, 970° C. orgreater, 980° C. or greater, 990° C. or greater, 1000° C. or greater,1010° C. or greater, about 1020° C. or greater, about 1030° C. orgreater, about 1040° C. or greater, about 1050° C. or greater, about1060° C. or greater, about 1070° C. or greater, about 1080° C. orgreater, about 1090° C. or greater, about 1100° C. or greater, about1150° C. or greater, about 1200° C. or greater, or about 1250° C. orgreater. In some embodiments, the glass composition or glass articlesformed from those compositions exhibit a T₂₀₀₀₀₀ in a range from about900° C. to about 1200° C., from about 925° C. to about 1200° C., fromabout 950° C. to about 1200° C., from about 975° C. to about 1200° C.,from about 1000° C. to about 1200° C., from about 1050° C. to about1200° C., from about 1100° C. to about 1200° C., from about 1150° C. toabout 1200° C., from about 1200° C. to about 1200° C., from about 900°C. to about 1190° C., from about 900° C. to about 1180° C., from about900° C. to about 1170° C., from about 900° C. to about 1160° C., fromabout 900° C. to about 1150° C., from about 900° C. to about 1140° C.,from about 900° C. to about 1130° C., from about 900° C. to about 1120°C., from about 900° C. to about 1110° C., from about 900° C. to about1100° C., from about 900° C. to about 1050° C., or from about 900° C. toabout 1000° C.

In some embodiments, the glass article exhibits a difference betweenT₂₀₀ and T₃₅₀₀₀ (or a relationship T₂₀₀−T₃₅₀₀₀) having a magnitude in arange from about 400° C. to about 600° C. For example, the differencebetween T₂₀₀ and T₃₅₀₀₀ may have a magnitude in a range from about 420°C. to about 600° C., from about 440° C. to about 600° C., from about450° C. to about 600° C., from about 460° C. to about 600° C., fromabout 480° C. to about 600° C., from about 500° C. to about 600° C.,from about 520° C. to about 600° C., from about 400° C. to about 580°C., from about 400° C. to about 560° C., from about 400° C. to about550° C., from about 400° C. to about 540° C., from about 450° C. toabout 560° C., or from about 460° C. to about 560° C.

In one or more embodiments, the glass article comprises a differencebetween the relationship (anneal point+softening point)/2 and T₂₀₀ ofless than −800° C. For example, the difference between the relationship(anneal point+softening point)/2 and T₂₀₀ is in a range from about−1050° C. to about −800° C., from about −1000° C. to about −800° C.,from about −950° C. to about −800° C., from about −900° C. to about−800° C., from about −1050° C. to about −850° C., from about −1050° C.to about −900° C., from about −1050° C. to about −950° C., or from about−1050° C. to about −1000° C.

In one or more embodiments, the glass article comprises a differencebetween the relationship (anneal point+softening point)/2 and T₃₅₀₀₀ ofless than −300° C. For example, the difference between the relationship(anneal point+softening point)/2 and T₃₅₀₀₀ is in a range from about−500° C. to about −300° C., from about −475° C. to about −300° C., fromabout −450° C. to about −300° C., from about −425° C. to about −300° C.,from about −400° C. to about −300° C., from about −500° C. to about−325° C., from about −500° C. to about −350° C., from about −500° C. toabout −375° C., or from about −500° C. to about −400° C.

In one or more embodiments, the glass article comprises a T₂₀₀, aT₃₅₀₀₀, or a T₂₀₀ and T₃₅₀₀₀ that are greater than about 1030° C. (e.g.,about 1035° C. or greater, about 1040° C. or greater, about 1045° C. orgreater, about 1050° C. or greater, about 1055° C. or greater, about1060° C. or greater, about 1065° C. or greater, or about 1070° C. orgreater).

In one or more embodiments, the glass composition or glass articlesformed from those compositions exhibit a sag temperature in a range fromabout 600° C. to about 720° C., from about 600° C. to about 700° C., orfrom about 620° C. to about 720° C. In one or more embodiments, theglass composition or glass articles formed from those compositionsexhibit a sag temperature in a range from about 605° C. to about 720°C., from about 610° C. to about 720° C., from about 615° C. to about720° C., from about 620° C. to about 720° C., from about 625° C. toabout 720° C., from about 630° C. to about 720° C., from about 635° C.to about 720° C., from about 640° C. to about 720° C., from about 645°C. to about 720° C., from about 650° C. to about 720° C., from about655° C. to about 720° C., from about 660° C. to about 720° C., fromabout 665° C. to about 720° C., from about 670° C. to about 720° C.,from about 620° C. to about 710° C., from about 620° C. to about 700°C., from about 620° C. to about 690° C., from about 620° C. to about680° C., from about 620° C. to about 670° C., from about 620° C. toabout 660° C., from about 620° C. to about 650° C., from about 620° C.to about 710° C., from about 625° C. to about 695° C., from about 625°C. to about 690° C., from about 625° C. to about 685° C., from about625° C. to about 680° C., from about 625° C. to about 675° C., fromabout 625° C. to about 670° C., from about 625° C. to about 665° C.,from about 625° C. to about 660° C., from about 625° C. to about 655°C., from about 625° C. to about 650° C., from about 630° C. to about710° C., from about 635° C. to about 710° C., from about 640° C. toabout 710° C., from about 645° C. to about 710° C., from about 650° C.to about 710° C., from about 655° C. to about 710° C., from about 660°C. to about 710° C., from about 665° C. to about 710° C., from about670° C. to about 710° C., from about 675° C. to about 710° C., fromabout 680° C. to about 710° C., from about 685° C. to about 710° C., orfrom about 690° C. to about 710° C. In one or more embodiments, theglass composition or glass article formed from such composition exhibitsa sag temperature in a range from about 600° C. to about 700° C., whilealso having a total alkali metal oxide content of about 16 mol % orgreater (e.g., about 17 mol % or greater, about 18 mol % or greater, orabout 19 mol % or greater).

In one or more embodiments, the glass composition or the glass articleformed therefrom comprise a log viscosity curve as a function oftemperature. An example of this curve is shown in FIG. 10.

In one or more embodiments, the glass composition or the glass articleformed therefrom exhibit a density at 20° C. that is less than about 2.6g/cm³. In one or more embodiments, the density of the glass compositionor the glass article formed therefrom is less than about 2.55 g/cm³. Forexample, the density of the glass composition or the glass articleformed therefrom is in a range from about 2.3 g/cm³ to about 2.6 g/cm³,from about 2.32 g/cm³ to about 2.6 g/cm³, from about 2.34 g/cm³ to about2.6 g/cm³, from about 2.35 g/cm³ to about 2.6 g/cm³, from about 2.36g/cm³ to about 2.6 g/cm³, from about 2.3 8 g/cm³ to about 2.6 g/cm³,from about 2.4 g/cm³ to about 2.6 g/cm³, from about 2.42 g/cm³ to about2.6 g/cm³, from about 2.44 g/cm³ to about 2.6 g/cm³, from about 2.45g/cm³ to about 2.6 g/cm³, from about 2.46 g/cm³ to about 2.6 g/cm³, fromabout 2.48 g/cm³ to about 2.6 g/cm³, from about 2.5 g/cm³ to about 2.6g/cm³, from about 2.3 g/cm³ to about 2.58 g/cm³, from about 2.3 g/cm³ toabout 2.56 g/cm³, from about2.3 g/cm³ to about 2.55 g/cm³, from about2.3 g/cm³ to about 2.54 g/cm³, from about2.3 g/cm³ to about 2.52 g/cm³,from about 2.3 g/cm³ to about2.5 g/cm³, from about 2.3 g/cm³ to about2.48 g/cm³, from about 2.3 g/cm³ to about 2.46 g/cm³, from about 2.3g/cm³ to about 2.45 g/cm³, from about2.3 g/cm³ to about 2.44 g/cm³, fromabout 2.3 g/cm³ to about 2.42 g/cm³, from about 2.3 g/cm³ to about 2.4g/cm³, from about 2.45 g/cm³ to about 2.52 g/cm³, or from about 2.48g/cm³ to about 2.55 g/cm³ _(,) The density was determined using thebuoyancy method of ASTM C693-93 (2013).

In one or more embodiments, the glass composition is fusion formable ascharacterized by its compatibility with current fusion-draw designsrequiring zircon refractory lining and hardware for isopipes. In someinstances, glass compositions can to react with the zircon, breaking thezircon down into silica, which dissolves in the glass, and zirconia,which forms solid inclusions that are entrained by flow into the moltenglass and ends up in the final glass article. The attack of zircon bythe molten glass continues over time and the level or concentration ofzirconia inclusions in the glass increases. If the temperature at whichthe zircon in the isopipe breaks down to form zirconia and silica (alsoreferred to herein as the “breakdown temperature” or “T^(breakdown)”) ishigher than any temperature seen on the isopipe, the problem of zirconiainclusions in fusion-drawn glass (also referred to as “fusion linezirconia”) would not occur. In this instance, the temperatures used toform the glass over the isopipe would be too low to create zirconia, andno such defect could form in the glass. Because fusion is essentially anisoviscous process, the highest temperature seen by the glasscorresponds to a particular viscosity of the glass. In those standardfusion-draw operations known in the art, this viscosity is about 35,000poise (“35 kPoise” or “35 kp”). In one or more embodiments, the glasscompositions described herein exhibit a zircon breakdown viscosity ofless than about 35 kP, while also exhibiting the other propertiesdescribed herein. In particular, the glass compositions described hereinexhibit a zircon breakdown viscosity in a range from about 6 kP up toabout 35 kP, while also exhibiting the relationship of (annealpoint+softening point)/2 in a range from about 625° C. to about 725° C.

Coefficients of thermal expansion (CTE) are expressed herein in terms ofparts per million (ppm)/° C. and represent a value measured over atemperature range from about 20° C. to about 300° C., unless otherwisespecified. High temperature (or liquid) coefficients of thermalexpansion (high temperature CTE) are also expressed in terms of part permillion (ppm) per degree Celsius (ppm/° C.), and represent a valuemeasured in the high temperature plateau region of the instantaneouscoefficient of thermal expansion (CTE) vs. temperature curve. The hightemperature CTE measures the volume change associated with heating orcooling of the glass through the transformation region.

In one or more embodiments, the glass article exhibits CTE measured overa temperature range from about 20° C. to about 300° C. in the range fromabout 75×10⁻⁷ ppm/° C. or greater, or about 80×10⁻⁷ ppm/° C.

In some embodiments, the glass article exhibits a high temperature (orliquid) CTE in the range from about 75×10⁻⁷ ppm/° C. to about 120×10⁻⁷ppm/° C., from about 80×10⁻⁷ ppm/° C. to about 120×10⁻⁷ ppm/° C., fromabout 85×10⁻⁷ ppm/° C. to about 120×10⁻⁷ ppm/° C., from about 90×10⁻⁷ppm/° C. to about 120×10⁻⁷ ppm/° C., from about 95×10⁻⁷ ppm/° C. toabout 120×10⁻⁷ ppm/° C., from about 100×10⁻⁷ ppm/° C. to about 120×10⁻⁷ppm/° C., from about 75×10⁻⁷ ppm/° C. to about 115×10⁻⁷ ppm/° C., fromabout 75×10⁻⁷ ppm/° C. to about 110×10⁻⁷ ppm/° C., from about 75×10⁻⁷ppm/° C. to about 105×10⁻⁷ ppm/° C., from about 75×10⁻⁷ ppm/° C. toabout 100×10⁻⁷ ppm/° C., from about 75×10⁻⁷ ppm/° C. to about 95×10⁻⁷ppm/° C., from about 80×10⁻⁷ ppm/° C. to about 100×10⁻⁷ ppm/° C., fromabout 90×10⁻⁷ ppm/° C. to about 100×10⁻⁷ ppm/° C., or from about 95×10⁻⁷ppm/° C. to about 100×10⁻⁷ ppm/° C.

In one or more embodiments, the glass article exhibits a Young's modulusin the range from about 70 GPa to about 85 GPa, from about 72 GPa toabout 85 GPa, from about 74 GPa to about 85 GPa, from about 75 GPa toabout 85 GPa, from about 76 GPa to about 85 GPa, from about 70 GPa toabout 80 GPa, from about 72 GPa to about 80 GPa, from about 74 GPa toabout 80 GPa, from about 75 GPa to about 80 GPa, from about 76 GPa toabout 80 GPa, from about 70 GPa to about 78 GPa, from about 70 GPa toabout 76 GPa, from about 70 GPa to about 75 GPa, from about 72 GPa toabout 78 GPa, from about 75 GPa to about 79 GPa, or from about 70 GPa toabout 77 GPa.

Referring to FIG. 3, embodiments of the glass article 100 include afirst major surface 102, an opposing second major surface 104 defining athickness t 110 between the first major surface and the second majorsurface.

In one or more embodiments, the thickness t may be about 3 millimetersor less (e.g., in the range from about 0.01 millimeter to about 3millimeters, from about 0.1 millimeter to about 3 millimeters, fromabout 0.2 millimeter to about 3 millimeters, from about 0.3 millimeterto about 3 millimeters, from about 0.4 millimeter to about 3millimeters, from about 0.01 millimeter to about 2.5 millimeters, fromabout 0.01 millimeter to about 2 millimeters, from about 0.01 millimeterto about 1.5 millimeters, from about 0.01 millimeter to about 1millimeter, from about 0.01 millimeter to about 0.9 millimeter, fromabout 0.01 millimeter to about 0.8 millimeter, from about 0.01millimeter to about 0.7 millimeter, from about 0.01 millimeter to about0.6 millimeter, from about 0.01 millimeter to about 0.5 millimeter, fromabout 0.1 millimeter to about 0.5 millimeter, or from about 0.3millimeter to about 0.5 millimeter.)

The glass article may be substantially planar sheet, although otherembodiments may utilize a curved or otherwise shaped or sculptedarticle. In some instances, the glass article may have a 3D or 2.5Dshape. Additionally or alternatively, the thickness of the glass articlemay be constant along one or more dimension or may vary along one ormore of its dimensions for aesthetic and/or functional reasons. Forexample, the edges of the glass article may be thicker as compared tomore central regions of the glass article. The length, width andthickness dimensions of the glass article may also vary according to thearticle application or use. In some embodiments, the glass article 100Amay have a wedged shape in which the thickness at one minor surface 106is greater than the thickness at an opposing minor surface 108, asillustrated in FIG. 3. Where the thickness varies, the thickness rangesdisclosed herein are the maximum thickness between the major surfaces.

The glass article may have a refractive index in the range from about1.45 to about 1.55. As used herein, the refractive index values are withrespect to a wavelength of 550 nm.

The glass article may be characterized by the manner in which it isformed. For instance, where the glass article may be characterized asfloat-formable (i.e., formed by a float process, or float-formed), ordown-drawable (i.e., formed by a down-draw process, or down-drawn).Particular examples of down draw processes include a fusion draw processor a slot draw process. Glass articles made by fusion draw processes arefusion formed, and glass articles formed by a slot draw process are slotdrawn.

Some embodiments of the glass articles described herein may be formed bya float process. A float-formed glass article may be characterized bysmooth surfaces and uniform thickness is made by floating molten glasson a bed of molten metal, typically tin. In an example process, moltenglass that is fed onto the surface of the molten tin bed forms afloating glass ribbon. As the glass ribbon flows along the tin bath, thetemperature is gradually decreased until the glass ribbon solidifiesinto a solid glass article that can be lifted from the tin onto rollers.Once off the bath, the glass article can be cooled further and annealedto reduce internal stress. In some embodiments, float formed glassarticles exhibit draw lines from the tin bath.

Some embodiments of the glass articles described herein may be formed bya down-draw process. Down-drawn glass articles have a uniform thicknessand relatively pristine surfaces. Because the average flexural strengthof the glass article is controlled by the amount and size of surfaceflaws, a pristine surface that has had minimal contact has a higherinitial strength. In addition, down drawn glass articles have a veryflat, smooth surface that can be used in its final application withoutcostly grinding and polishing.

The fusion process uses a drawing tank that has a channel for acceptingmolten glass raw material. The channel has weirs that are open at thetop along the length of the channel on both sides of the channel. Whenthe channel fills with molten material, the molten glass overflows theweirs. Due to gravity, the molten glass flows down the outside surfacesof the drawing tank as two flowing glass films. These outside surfacesof the drawing tank extend down and inwardly so that they join at anedge below the drawing tank. The two flowing glass films join at thisedge to fuse and form a single flowing glass article. The fusion drawmethod offers the advantage that, because the two glass films flowingover the channel fuse together, neither of the outside surfaces of theresulting glass article comes in contact with any part of the apparatus.Thus, the surface properties of the fusion drawn glass article are notaffected by such contact.

Some embodiments of the glass articles described herein may be formed bya slot draw process. The slot draw process is distinct from the fusiondraw method. In slow draw processes, the molten raw material glass isprovided to a drawing tank. The bottom of the drawing tank has an openslot with a nozzle that extends the length of the slot. The molten glassflows through the slot/nozzle and is drawn downward as a continuousglass article and into an annealing region.

In one or more embodiments, the glass articles described herein mayexhibit an amorphous microstructure and may be substantially free ofcrystals or crystallites. In other words, the glass articles excludeglass-ceramic materials.

In one or more embodiments, the glass article exhibits a total solartransmittance of about 90% or less, over a wavelength range from about300 nm to about 2500 nm, when the glass article has a thickness of 0.7mm. For example, the glass article exhibits a total solar transmittancein a range from about 60% to about 88%, from about 62% to about 88%,from about 64% to about 88%, from about 65% to about 88%, from about 66%to about 88%, from about 68% to about 88%, from about 70% to about 88%,from about 72% to about 88%, from about 60% to about 86%, from about 60%to about 85%, from about 60% to about 84%, from about 60% to about 82%,from about 60% to about 80%, from about 60% to about 78%, from about 60%to about 76%, from about 60% to about 75%, from about 60% to about 74%,or from about 60% to about 72%.

In one or embodiments, the glass article exhibits an averagetransmittance in the range from about 75% to about 85%, at a thicknessof 0.7 mm or 1 mm, over a wavelength range from about 380 nm to about780 nm. In some embodiments, the average transmittance at this thicknessand over this wavelength range may be in a range from about 75% to about84%, from about 75% to about 83%, from about 75% to about 82%, fromabout 75% to about 81%, from about 75% to about 80%, from about 76% toabout 85%, from about 77% to about 85%, from about 78% to about 85%,from about 79% to about 85%, or from about 80% to about 85%. In one ormore embodiments, the glass article exhibits T_(uv-380) or T_(uv-400) of50% or less (e.g., 49% or less, 48% or less, 45% or less, 40% or less,30% or less, 25% or less, 23% or less, 20% or less, or 15% or less), ata thickness of 0.7 mm or 1 mm, over a wavelength range from about 300 nmto about 400 nm.

In one or more embodiments, the glass article may be strengthened toinclude compressive stress (CS) that extends from a surface to a depthof compression (DOC). The surface (CS) regions are balanced by a centralportion exhibiting a tensile stress (CT). At the DOC, the stress crossesfrom a positive (compressive) stress to a negative (tensile) stress;however compressive stress and tensile stress values provided herein areabsolute values.

In one or more embodiments, the glass article may be strengthenedmechanically by utilizing a mismatch of the coefficient of thermalexpansion between portions of the article to create a compressive stressregion and a central region exhibiting a tensile stress. In someembodiments, the glass article may be strengthened thermally by heatingthe glass to a temperature below the glass transition point and thenrapidly quenching.

In one or more embodiments, the glass article may be chemicallystrengthening by ion exchange. In the ion exchange process, ions at ornear the surface of the glass article are replaced by—or exchangedwith—larger ions having the same valence or oxidation state. In thoseembodiments in which the glass article comprises an alkalialuminosilicate glass, ions in the surface layer of the article and thelarger ions are monovalent alkali metal cations, such as Li⁺, Na⁺, K⁺,Rb⁺, and Cs⁺. Alternatively, monovalent cations in the surface layer maybe replaced with monovalent cations other than alkali metal cations,such as Ag⁺ or the like. In such embodiments, the monovalent ions (orcations) exchanged into the glass article generate a stress.

Ion exchange processes are typically carried out by immersing a glassarticle in a molten salt bath (or two or more molten salt baths)containing the larger ions to be exchanged with the smaller ions in theglass article. It should be noted that aqueous salt baths may also beutilized. In addition, the composition of the bath(s) may include morethan one type of larger ion (e.g., Na+ and K+) or a single larger ion.It will be appreciated by those skilled in the art that parameters forthe ion exchange process, including, but not limited to, bathcomposition and temperature, immersion time, the number of immersions ofthe glass article in a salt bath (or baths), use of multiple salt baths,additional steps such as annealing, washing, and the like, are generallydetermined by the composition of the glass article (including thestructure of the article and any crystalline phases present) and thedesired DOC and CS of the glass article that results from strengthening.Exemplary molten bath composition may include nitrates, sulfates, andchlorides of the larger alkali metal ion. Typical nitrates include KNO₃,NaNO₃, LiNO₃, NaSO₄ and combinations thereof. The temperature of themolten salt bath typically is in a range from about 380° C. up to about450° C., while immersion times range from about 15 minutes up to about100 hours depending on glass article thickness, bath temperature andglass (or monovalent ion) diffusivity. However, temperatures andimmersion times different from those described above may also be used.

In one or more embodiments, the glass articles may be immersed in amolten salt bath of 100% NaNO₃, 100% KNO₃, or a combination of NaNO₃ andKNO₃ having a temperature in a range from about 370° C. to about 480° C.

In some embodiments, the glass article may be immersed in a molten mixedsalt bath including from about 5% to about 90% KNO₃ and from about 10%to about 95% NaNO₃. In one or more embodiments, the glass article may beimmersed in a second bath, after immersion in a first bath. The firstand second baths may have different compositions and/or temperaturesfrom one another. The immersion times in the first and second baths mayvary. For example, immersion in the first bath may be longer than theimmersion in the second bath.

In one or more embodiments, the glass article may be immersed in amolten, mixed salt bath including NaNO₃ and KNO₃ (e.g., 49%/51%,50%/50%, 51%/49%) having a temperature less than about 420° C. (e.g.,about 400° C. or about 380° C.). for less than about 5 hours, or evenabout 4 hours or less.

Ion exchange conditions can be tailored to provide a “spike” or toincrease the slope of the stress profile at or near the surface of theresulting glass article. The spike may result in a greater surface CSvalue. This spike can be achieved by single bath or multiple baths, withthe bath(s) having a single composition or mixed composition, due to theunique properties of the glass compositions used in the glass articlesdescribed herein.

In one or more embodiments, where more than one monovalent ion isexchanged into the glass article, the different monovalent ions mayexchange to different depths within the glass article (and generatedifferent magnitudes stresses within the glass article at differentdepths). The resulting relative depths of the stress-generating ions canbe determined and cause different characteristics of the stress profile.

Surface CS is measured using those means known in the art, such as bysurface stress meter (FSM) using commercially available instruments suchas the FSM-6000, manufactured by Orihara Industrial Co., Ltd. (Japan).Surface stress measurements rely upon the accurate measurement of thestress optical coefficient (SOC), which is related to the birefringenceof the glass. SOC in turn is measured by those methods that are known inthe art, such as fiber and four point bend methods, both of which aredescribed in ASTM standard C770-98 (2013), entitled “Standard TestMethod for Measurement of Glass Stress-Optical Coefficient,” thecontents of which are incorporated herein by reference in theirentirety, and a bulk cylinder method. As used herein CS may be the“maximum compressive stress” which is the highest compressive stressvalue measured within the compressive stress layer. In some embodiments,the maximum compressive stress is located at the surface of the glassarticle. In other embodiments, the maximum compressive stress may occurat a depth below the surface, giving the compressive profile theappearance of a “buried peak.”

DOC may be measured by FSM or by a scattered light polariscope (SCALP)(such as the SCALP-04 scattered light polariscope available fromGlasstress Ltd., located in Tallinn, Estonia), depending on thestrengthening method and conditions. When the glass article ischemically strengthened by an ion exchange treatment, FSM or SCALP maybe used depending on which ion is exchanged into the glass article.Where the stress in the glass article is generated by exchangingpotassium ions into the glass article, FSM is used to measure DOC. Wherethe stress is generated by exchanging sodium ions into the glassarticle, SCALP is used to measure DOC. Where the stress in the glassarticle is generated by exchanging both potassium and sodium ions intothe glass, the DOC is measured by SCALP, since it is believed theexchange depth of sodium indicates the DOC and the exchange depth ofpotassium ions indicates a change in the magnitude of the compressivestress (but not the change in stress from compressive to tensile); theexchange depth of potassium ions in such glass articles is measured byFSM.

In one or more embodiments, the glass article may be strengthened toexhibit a DOC that is described a fraction of the thickness t of theglass article (as described herein). For example, in one or moreembodiments, the DOC may be equal to or greater than about 0.03 t, equalto or greater than about 0.05 t, equal to or greater than about 0.06 t,equal to or greater than about 0.1 t, equal to or greater than about0.11 t, equal to or greater than about 0.12 t, equal to or greater thanabout 0.13 t, equal to or greater than about 0.14 t, equal to or greaterthan about 0.15 t, equal to or greater than about 0.16 t, equal to orgreater than about 0.17 t, equal to or greater than about 0.18 t, equalto or greater than about 0.19 t, equal to or greater than about 0.2 t,equal to or greater than about 0.21 t. In some embodiments, The DOC maybe in a range from about 0.03 t to about 0.25 t, from about 0.04 t toabout 0.25 t, from about 0.05 t to about 0.25 t, from about 0.06 t toabout 0.25 t, from about 0.07 t to about 0.25 t, from about 0.08 t toabout 0.25 t, from about 0.09 t to about 0.25 t, from about 0.18 t toabout 0.25 t, from about 0.1 it to about 0.25 t, from about 0.12 t toabout 0.25 t, from about 0.13 t to about 0.25 t, from about 0.14 t toabout 0.25 t, from about 0.15 t to about 0.25 t, from about 0.03 t toabout 0.24 t, from about 0.03 t to about 0.23 t, from about 0.03 t toabout 0.22 t, from about 0.03 t to about 0.21 t, from about 0.03 t toabout 0.2 t, from about 0.03 t to about 0.19 t, from about 0.03 t toabout 0.18 t, from about 0.03 t to about 0.17 t, from about 0.03 t toabout 0.16 t, or from about 0.03 t to about 0.15 t. In some instances,the DOC may be about 20 μm or less. In one or more embodiments, the DOCmay be about 35 μm or greater (e.g., from about 40 μm to about300 μm,from about 50 μm to about300 μm, from about 60 μm to about300 μm, fromabout 70 μm to about300 μm, from about 80 μm to about300 μm, from about90 μm to about 300 μm, from about 100 μm to about 300 μm, from about 110μm to about 300 μm, from about 120 μm to about 300 μm, from about 140 μmto about 300 μm, from about 150 μm to about 300 μm, from about40 μm toabout 290 μm, from about40 μm to about 280 μm, from about 40 μm to about260 μm, from about 40 μm to about 250 μm, from about 40 μm to about 240μm, from about40 μm to about 230 μm, from about40 μm to about 220 μm,from about 40 μm to about 210 μm, from about 40 μm to about 200 μm, fromabout 40 μm to about 180 μm, from about40 μm to about 160 μm, fromabout40 μm to about 150 μm, from about40 μm to about 140 μm, fromabout40 μm to about 130 μm, from about40 μm to about 120 μm, from about40 μm to about 110 μm, or from about 40 μm to about 100 μm).

In one or more embodiments, the strengthened glass article may have a CS(which may be found at the surface or a depth within the glass article)of about 200 MPa or greater, 300 MPa or greater,400 MPa or greater,about 500 MPa or greater, about 600 MPa or greater, about 700 MPa orgreater, about 800 MPa or greater, about 900 MPa or greater, about 930MPa or greater, about 1000 MPa or greater, or about 1050 MPa or greater.

In one or more embodiments, the strengthened glass article may have amaximum CT of about 20 MPa or greater, about 30 MPa or greater, about 40MPa or greater, about 45 MPa or greater, about 50 MPa or greater, about60 MPa or greater, about 70 MPa or greater, about 75 MPa or greater,about 80 MPa or greater, or about 85 MPa or greater. In someembodiments, the maximum CT may be in a range from about 40 MPa to about100 MPa.

In one or more particular embodiments, the glass article glass article(having a thickness of about 1 mm or less) exhibits a surface CS in arange from about 650 MPa to about 850 MPa and a corresponding DOC in arange from about 35 micrometers to about 65 micrometers. In suchembodiments, the strengthening levels (in terms of surface CS and DOC)is exhibited by the glass article after being immersed in a molten saltbath of 100% KNO₃ for less than about 8 hours, about 6 hours or less, orabout 4 hours or less. The temperature may be in a range from about 380°C. to about 420° C.

Another aspect of this disclosure pertains to a laminate comprising aglass article as described herein. In one or more embodiments, thelaminate 200 may include a first glass layer 210 comprising a glassarticle according to one or more embodiments, and an interlayer 220disposed on the first glass layer, as illustrated in FIG. 4. As shown inFIG. 5, the laminate 300 may include a first glass layer 310, aninterlayer 320 disposed on the first layer, and a second glass layer 330disposed on the interlayer 320 opposite the first glass layer 310.Either one or both of the first glass layer and the second glass layerused in the laminate can include a glass article described herein. Asshown in FIG. 5, the interlayer 320 is disposed between the first andsecond glass layers.

In one or more embodiments, the laminate 300 may include a first glasslayer comprising a glass article as described herein, and a second glasslayer that includes a different composition than the glass articlesdescribed herein. For example, the second glass layer may includesoda-lime glass, alkali aluminosilicate glass, alkali containingborosilicate glass, alkali aluminophosphosilicate glass, or alkalialuminoborosilicate glass. In some embodiments, both the first andsecond glass layers are comprise a glass article described herein, whichmay be the same or different from one another.

In one or more embodiments, either one or both the first glass layer andthe second glass layer comprise a thickness less than 1.6 mm (e.g., 1.55mm or less, 1.5 mm or less, 1.45 mm or less, 1.4 mm or less, 1.35 mm orless, 1.3 mm or less, 1.25 mm or less, 1.2 mm or less, 1.15 mm or less,1.1 mm or less, 1.05 mm or less, 1 mm or less, 0.95 mm or less, 0.9 mmor less, 0.85 mm or less, 0.8 mm or less, 0.75 mm or less, 0.7 mm orless, 0.65 mm or less, 0.6 mm or less, 0.55 mm or less, 0.5 mm or less,0.45 mm or less, 0.4 mm or less, 0.35 mm or less, 0.3 mm or less, 0.25mm or less, 0.2 mm or less, 0.15 mm or less, or about 0.1 mm or less).The lower limit of thickness may be 0.1 mm, 0.2 mm or 0.3 mm. In someembodiments, the thickness of either one or both the first glass layerand the second glass layer is in the range from about 0.1 mm to lessthan about 1.6 mm, from about 0.1 mm to about 1.5 mm, from about 0.1 mmto about 1.4 mm, from about 0.1 mm to about 1.3 mm, from about 0.1 mm toabout 1.2 mm, from about 0.1 mm to about 1.1 mm, from about 0.1 mm toabout 1 mm, from about 0.1 mm to about 0.9 mm, from about 0.1 mm toabout 0.8 mm, from about 0.1 mm to about 0.7 mm, from about 0.1 mm, fromabout 0.2 mm to less than about 1.6 mm, from about 0.3 mm to less thanabout 1.6 mm, from about 0.4 mm to less than about 1.6 mm, from about0.5 mm to less than about 1.6 mm, from about 0.6 mm to less than about1.6 mm, from about 0.7 mm to less than about 1.6 mm, from about 0.8 mmto less than about 1.6 mm, from about 0.9 mm to less than about 1.6 mm,from about 1 mm to about 1.6 mm, from about 0.4 mm to about 1.2 mm, fromabout 0.5 mm to about 1.2 mm, from about 0.7 mm to about 1.2 mm, fromabout 0.4 mm to about 1 mm, from about 0.5 mm to about 1 mm, or fromabout 0.7 mm to about 1 mm. In some embodiments, the first glass layerand the second glass layer have substantially the same thickness as oneanother.

In some embodiments, while one of the first and second glass layers hasa thickness less than about 1.6 mm, the other of the first and secondglass layers has a thickness that is about 1 mm or greater, or about 1.6mm or greater. In one or more embodiments, the first and the secondglass layers have thicknesses that differ from one another. For example,the while one of the first and second glass layers has a thickness lessthan about 1.6 mm, the other of the first and second glass layers has athickness that is about 1.7 mm or greater, about 1.75 mm or greater,about 1.8 mm or greater, about 1.7 mm or greater, about 1.7 mm orgreater, about 1.7 mm or greater, about 1.85 mm or greater, about 1.9 mmor greater, about 1.95 mm or greater, about 2 mm or greater, about 2.1mm or greater, about 2.2 mm or greater, about 2.3 mm or greater, about2.4 mm or greater, 2.5 mm or greater, 2.6 mm or greater, 2.7 mm orgreater, 2.8 mm or greater, 2.9 mm or greater, 3 mm or greater, 3.2 mmor greater, 3.4 mm or greater, 3.5 mm or greater, 3.6 mm or greater, 3.8mm or greater, 4 mm or greater, 4.2 mm or greater, 4.4 mm or greater,4.6 mm or greater, 4.8 mm or greater, 5 mm or greater, 5.2 mm orgreater, 5.4 mm or greater, 5.6 mm or greater, 5.8 mm or greater, or 6mm or greater. In some embodiments the first and/or second glass layershas a thickness in a range from about 1.6 mm to about 6 mm, from about1.7 mm to about 6 mm, from about 1.8 mm to about 6 mm, from about 1.9 mmto about 6 mm, from about 2 mm to about 6 mm, from about 2.1 mm to about6 mm, from about 2.2 mm to about 6 mm, from about 2.3 mm to about 6 mm,from about 2.4 mm to about 6 mm, from about 2.5 mm to about 6 mm, fromabout 2.6 mm to about 6 mm, from about 2.8 mm to about 6 mm, from about3 mm to about 6 mm, from about 3.2 mm to about 6 mm, from about 3.4 mmto about 6 mm, from about 3.6 mm to about 6 mm, from about 3.8 mm toabout 6 mm, from about 4 mm to about 6 mm, from about 1.6 mm to about5.8 mm, from about 1.6 mm to about 5.6 mm, from about 1.6 mm to about5.5 mm, from about 1.6 mm to about 5.4 mm, from about 1.6 mm to about5.2 mm, from about 1.6 mm to about 5 mm, from about 1.6 mm to about 4.8mm, from about 1.6 mm to about 4.6 mm, from about 1.6 mm to about 4.4mm, from about 1.6 mm to about 4.2 mm, from about 1.6 mm to about 4 mm,from about 3.8 mm to about 5.8 mm, from about 1.6 mm to about 3.6 mm,from about 1.6 mm to about 3.4 mm, from about 1.6 mm to about 3.2 mm, orfrom about 1.6 mm to about 3 mm.

In one or more embodiments the first glass layer is relatively thin incomparison to the second glass layer. In other words, the second glasslayer has a thickness greater than the first glass layer. In one or moreembodiments, the second glass layer may have a thickness that is morethan two times the thickness of the first glass layer. In one or moreembodiments, the second glass layer may have a thickness in the rangefrom about 1.5 times to about 2.5 times the thickness of the first glasslayer.

In one or more embodiments, the first glass layer and the second glasslayer may have the same thickness; however, the second glass layer ismore rigid or has a greater stiffness than the first glass layer, and invery specific embodiments, both the first glass layer and the secondglass layer have a thickness in the range of 0.2 mm and 1.6 mm.

In one or more embodiments, the laminate 200, 300 may have a thicknessof 6.85 mm or less, or 5.85 mm or less, where the thickness comprisesthe sum of thicknesses of the first glass layer, the second glass layer,the interlayer and any other layers. In various embodiments, thelaminate may have a thickness in the range of about 1.8 mm to about 6.85mm, or in the range of about 1.8 mm to about 5.85 mm, or in the range ofabout 1.8 mm to about 5.0 mm, or 2.1 mm to about 6.85 mm, or in therange of about 2.1 mm to about 5.85 mm, or in the range of about 2.1 mmto about 5.0 mm, or in the range of about 2.4 mm to about 6.85 mm, or inthe range of about 2.4 mm to about 5.85 mm, or in the range of about 2.4mm to about 5.0 mm, or in the range of about 3.4 mm to about 6.85 mm, orin the range of about 3.4 mm to about 5.85 mm, or in the range of about3.4 mm to about 5.0 mm.

In one or more embodiments, the laminate 300, 400 exhibits at least oneradius of curvature that is less than 1000 mm, or less than 750 mm, orless than 500 mm, or less than 300 mm. In one or more embodiments, thelaminate 300 exhibits at least one radius of curvature of about 10 m orless, or about 5 m or less along at least one axis. In one or moreembodiments, the laminate 400 may have a radius of curvature of 5 m orless along at least a first axis and along the second axis that isperpendicular to the first axis. In one or more embodiments, thelaminate may have a radius of curvature of 5 m or less along at least afirst axis and along the second axis that is not perpendicular to thefirst axis.

In one or more embodiments, the first glass layer has a first sagtemperature and the second glass layer has a second sag temperature,wherein the difference between the first sag temperature and the secondsag temperature is about 100° C. or less, about 90° C. or less, about80° C. or less, about 75° C. or less, about 70° C. or less, about 60° C.or less, about 50° C. or less, about 40° C. or less, about 30° C. orless, about 20° C. or less, or about 10° C. or less.

In one or more embodiments, the first or second glass layer may utilizea glass article that is strengthened, as described herein. In one ormore embodiments, the first glass layer comprises a strengthened glassarticle according to the embodiments described herein, while the secondglass layer is not strengthened. In one or more embodiments, the firstglass layer comprises a strengthened glass article according to theembodiments described herein, while the second glass layer is annealed.In one or more embodiments, the first glass layer is strengthenedchemically, mechanically and/or thermally, while the second glass layeris strengthened in different manner than the first glass layer(chemically, mechanically and/or thermally). In one or more embodiments,the first glass layer is strengthened chemically, mechanically and/orthermally, while the second glass layer is strengthened in the samemanner than the first glass layer (chemically, mechanically and/orthermally).

In one or more embodiments, the interlayer used herein (e.g., 320) mayinclude a single layer or multiple layers. The interlayer (or layersthereof) may be formed polymers such as polyvinyl butyral (PVB),acoustic PBV (APVB), ionomers, ethylene-vinyl acetate (EVA) andthermoplastic polyurethane (TPU), polyester (PE), polyethyleneterephthalate (PET) and the like. The thickness of the interlayer may bein the range from about 0.5 mm to about 2.5 mm, from about 0.8 mm toabout 2.5 mm, from about 1 mm to about 2.5 mm or from about 1.5 mm toabout 2.5 mm.

Another aspect of this disclosure pertains to a laminate 400 comprisinga first curved glass layer 410, a second curved glass layer 420 and aninterlayer 530 disposed between the first curved glass layer and thesecond curved glass layer, as illustrated in FIG. 6. In one or moreembodiments, the first curved glass layer 410 includes a first majorsurface 412, a second major surface 414 opposing the first majorsurface, a first thickness 416 defined as the distance between the firstmajor surface and second major surface, and a first sag depth 418. Inone or more embodiments, the second curved glass layer 420 includes athird major surface 422, a fourth major surface 424 opposing the thirdmajor surface, a second thickness 426 defined as the distance betweenthe third major surface and the fourth major surface, and a second sagdepth 428. The orientation of the laminate 400 of FIG. 6 shows thesecond surface 414 as a convex surface and the third surface 422 as aconcave surface. In one or more embodiments, the positions of the firstcurved glass layer can be reversed. In one or more embodiments, thefirst curved glass layer exhibits a first viscosity and the secondcurved glass layer exhibits a second viscosity that differs from thefirst viscosity at a given temperature. In one or more embodiments, thefirst curved glass layer is formed from one or more embodiments of theglass compositions described herein. The temperature at which the firstviscosity and second viscosity is measured may be from about 590° C. toabout 650° C. (or about 630° C.). In some embodiments, the firstviscosity is equal to or greater than about 2 times, about 3 times,about 4 times, about 5 times, about 6 times, about 7 times, about 8times, about 9 times, or about 10 times the first viscosity, at atemperature of 630° C.

In one or more embodiments, at 600° C., the first viscosity is in arange from about 2×10¹¹ poises to about 1×10¹⁵ poises, from about 4×10¹¹poises to about 1×10¹⁵ poises, from about 5×10¹¹ poises to about 1×10¹⁵poises, from about 6×10¹¹ poises to about 1×10¹⁵ poises, from about8×10¹¹ poises to about 1×10¹⁵ poises, from about 1×10¹² poises to about1×10¹⁵ poises, from about 2×10¹² poises to about 1×10¹⁵ poises, fromabout 4×10¹² poises to about 1×10¹⁵ poises, from about 5×10¹² poises toabout 1×10¹⁵ poises, from about 6×10¹² poises to about 1×10¹⁵ poises,from about 8×10¹² poises to about 1×10¹⁵ poises, from about 1×10¹³poises to about 1×10¹⁵ poises, from about 2×10¹³ poises to about 1×10¹⁵poises, from about 4×10¹³ poises to about 1×10¹⁵ poises, from about5×10¹³ poises to about 1×10¹⁵ poises, from about 6×10¹³ poises to about1×10¹⁵ poises, from about 8×10¹³ poises to about 1×10¹⁵ poises, fromabout 1×10¹⁴ poises to about 1×10¹⁵ poises, from about 2×10¹¹ poises toabout 8×10¹⁴ poises, from about 2×10¹¹ poises to about 6×10¹⁴ poises,from about 2×10¹¹ poises to about 5×10¹⁴ poises, from about 2×10¹¹poises to about 4×10¹⁴ poises, from about 2×10¹¹ poises to about 2×10¹⁴poises, from about 2×10¹¹ poises to about 1×10¹⁴ poises, from about2×10¹¹ poises to about 8×10¹³ poises, from about 2×10¹¹ poises to about6×10¹³ poises, from about 2×10¹¹ poises to about 5×10¹³ poises, fromabout2×10¹¹ poises to about 4×10¹³ poises, from about2×10¹¹ poises toabout 2×10¹³ poises, from about 2×10¹¹ poises to about 1×10¹³ poises,from about 2×10¹¹ poises to about 8×10¹² poises, from about 2×10¹¹poises to about 6×10¹² poises, or from about 2×10¹¹ poises to about5×10¹² poises.

In one or more embodiments, at 630° C., the first viscosity is in arange from about 2×10¹° poises to about 1×10¹³ poises, from about 4×10¹°poises to about 1×10¹³ poises, from about 5×10¹⁰ poises to about 1×10¹³poises, from about 6×10¹⁰ poises to about 1×10¹³ poises, from about8×10¹⁰ poises to about 1×10¹³ poises, from about 1×10¹¹ poises to about1×10¹³ poises, from about 2×10¹¹ poises to about 1×10¹³ poises, fromabout 4×10¹¹ poises to about 1×10¹³ poises, from about 5×10¹¹ poises toabout 1×10¹³ poises, from about 6×10¹¹ poises to about 1×10¹³ poises,from about 8×10¹¹ poises to about 1×10¹³ poises, from about 1×10¹²poises to about 1×10¹³ poises, from about 2×10¹⁰ poises to about 8×10¹²poises, from about 2×10¹⁰ poises to about 6×10¹² poises, from about2×10¹⁰ poises to about 5×10¹² poises, from about 2×10¹⁰ poises to about4×10¹² poises, from about 2×10¹° poises to about 2×10¹² poises, fromabout 2×10¹° poises to about 1×10¹² poises, from about 2×10¹⁰ poises toabout 8×10¹¹ poises, from about 2×10¹⁰ poises to about 6×10¹¹ poises,from about 2×10¹⁰ poises to about 5×10¹¹ poises, from about 2×10¹⁰poises to about 4×10¹¹ poises, or from about 2×10¹⁰ poises to about2×10¹¹ poises.

In one or more embodiments, at 650° C., the first viscosity is in arange from about 1×10¹° poises to about 1×10¹³ poises, from about 2×10¹°poises to about 1×10¹³ poises, from about 4×10¹⁰ poises to about 1×10¹³poises, from about 5×10¹⁰ poises to about 1×10¹³ poises, from about6×10¹⁰ poises to about 1×10¹³ poises, from about 8×10¹⁰ poises to about1×10¹³ poises, from about 1×10¹¹ poises to about 1×10¹³ poises, fromabout 2×10¹¹ poises to about 1×10¹³ poises, from about 4×10¹¹ poises toabout 1×10¹³ poises, from about 4×10¹¹ poises to about 1×10¹³ poises,from about 5×10¹¹ poises to about 1×10¹³ poises, from about 6×10¹¹poises to about 1×10¹³ poises, from about 8×10¹¹ poises to about 1×10¹³poises, from about 1×10¹² poises to about 1×10¹³ poises, from about1×10¹⁰ poises to about 8×10¹² poises, from about 1×10¹⁰ poises to about6×10¹² poises, from about 1×10¹⁰ poises to about 5×10¹² poises, fromabout 1×10¹⁰ poises to about 4×10¹² poises, from about 1×10¹⁰ poises toabout 2×10¹² poises, from about 1×10¹⁰ poises to about 1×10¹² poises,from about 1×10¹⁰ poises to about 8×10¹¹ poises, from about 1×10¹⁰poises to about 6×10¹¹ poises, from about 1×10¹⁰ poises to about 5×10¹¹poises, from about 1×10¹⁰ poises to about 4×10¹¹ poises, from about1×10¹⁰ poises to about 2×10¹¹ poises, or from about 1×10¹⁰ poises toabout 1×10¹¹ poises.

In one or more embodiments, at 600° C., the second viscosity is in arange from about 3×10¹⁰ poises to about 8×10¹⁰ poises, from about 4×10¹⁰poises to about 8×10¹⁰ poises, from about 5×10¹⁰ poises to about 8×10¹⁰poises, from about 6×10¹⁰ poises to about 8×10¹⁰ poises, from about3×10¹⁰ poises to about 7×10¹⁰ poises, from about 3×10¹⁰ poises to about6×10¹⁰ poises, from about 3×10¹⁰ poises to about 5×10¹⁰ poises, or fromabout 4×10¹⁰ poises to about 6×10¹⁰ poises.

In one or more embodiments, at 630° C., the second viscosity is in arange from about 1×10⁹ poises to about 1×10¹° poises, from about 2×10⁹poises to about 1×10¹⁰ poises, from about 3×10⁹ poises to about 1×10¹°poises, from about 4×10⁹ poises to about 1×10¹° poises, from about 5×10⁹poises to about 1×10¹° poises, from about 6×10⁹ poises to about 1×10¹⁰poises, from about 1×10⁹ poises to about 9×10⁹ poises, from about 1×10⁹poises to about 8×10⁹ poises, from about 1×10⁹ poises to about 7×10 ⁹poises, from about 1×10⁹ poises to about 6×10⁹ poises, from about 4×10⁹poises to about 8×10⁹ poises, or from about 5×10⁹ poises to about 7×10⁹poises.

In one or more embodiments, at 650° C., the second viscosity is in arange from about 5×10⁸ poises to about 5×10⁹ poises, from about 6×10⁸poises to about 5×10⁹ poises, from about 7×10⁸ poises to about 5×10⁹poises, from about 8×10⁸ poises to about 5×10⁹ poises, from about 9×10⁸poises to about 5×10⁹ poises, from about 1×10⁹poises to about 5×10⁹poises, from about 1×10⁹poises to about 4×10⁹ poises, from about1×10⁹poises to about 3×10⁹ poises, from about 5×10⁸ poises to about4×10⁹ poises, from about 5×10⁸ poises to about 3×10⁹ poises, from about5×10⁸poises to about 2×10⁹ poises, from about 5×10⁸ poises to about1×10⁹ poises, from about 5×10⁸ poises to about 9×10⁸ poises, from about5×10⁸ poises to about 8×10⁸ poises, or from about 5×10⁸ poises to about7×10⁸ poises.

In one or more embodiments, one or both the first sag depth 418 and thesecond sag depth 428 is about 2 mm or greater. For example, one or boththe first sag depth 418 and the second sag depth 428 may be in a rangefrom about 2 mm to about 30 mm, from about 4 mm to about 30 mm, fromabout 5 mm to about 30 mm, from about 6 mm to about 30 mm, from about 8mm to about 30 mm, from about 10 mm to about 30 mm, from about 12 mm toabout 30 mm, from about 14 mm to about 30 mm, from about 15 mm to about30 mm, from about 2 mm to about 28 mm, from about 2 mm to about 26 mm,from about 2 mm to about 25 mm, from about 2 mm to about 24 mm, fromabout 2 mm to about 22 mm, from about 2 mm to about 20 mm, from about 2mm to about 18 mm, from about 2 mm to about 16 mm, from about 2 mm toabout 15 mm, from about 2 mm to about 14 mm, from about 2 mm to about 12mm, from about 2 mm to about 10 mm, from about 2 mm to about 8 mm, fromabout 6 mm to about 20 mm, from about 8 mm to about 18 mm, from about 10mm to about 15 mm, from about 12 mm to about 22 mm, from about 15 mm toabout 25 mm, or from about 18 mm to about 22 mm.

In one or more embodiments, the first sag depth 418 and the second sagdepth 428 are substantially equal to one another. In one or moreembodiments, the first sag depth is within 10% of the second sag depth.For example, the first sag depth is within 9%, within 8%, within 7%,within 6% or within 5% of the second sag depth. For illustration, thesecond sag depth is about 15 mm, and the first sag depth is in a rangefrom about 14.5 mm to about 16.5 mm (or within 10% of the second sagdepth).

In one or more embodiments, the first curved glass layer and the secondcurved glass layer comprise a shape deviation therebetween of ±5 mm orless as measured by an optical three-dimensional scanner such as theATOS Triple Scan supplied by GOM GmbH, located in Braunschweig, Germany.In one or more embodiments, the shape deviation is measured between thesecond surface 414 and the third surface 422, or between the firstsurface 412 and the fourth surface 424. In one or more embodiments, theshape deviation between the first glass layer and the second glass layeris about ±4 mm or less, about ±3 mm or less, about ±2 mm or less, about±1 mm or less, about ±0.8 mm or less, about ±0.6 mm or less, about ±0.5mm or less, about ±0.4 mm or less, about ±0.3 mm or less, about ±0.2 mmor less, or about ±0.1 mm or less. As used herein, the shape deviationrefers to the maximum shape deviation measured on the respectivesurfaces.

In one or more embodiments, one of or both the first major surface 412and the fourth major surface 424 exhibit minimal optical distortion. Forexample, one of or both the first major surface 412 and the fourth majorsurface 424 exhibit optical distortion of less than about 400millidiopters, less than about 300 millidiopters, or less than about 250millidiopters, as measured by an optical distortion detector usingtransmission optics according to ASTM 1561. A suitable opticaldistortion detector is supplied by ISRA VISIION AG, located inDarmstadt, Germany, under the tradename SCREENSCAN-Faultfinder. In oneor more embodiments, one of or both the first major surface 312 and thefourth major surface 324 exhibit optical distortion of about 190millidiopters or less, about 180 millidiopters or less, about 170millidiopters or less, about 160 millidiopters or less, about 150millidiopters or less, about 140 millidiopters or less, about 130millidiopters or less, about 120 millidiopters or less, about 110millidiopters or less, about 100 millidiopters or less, about 90millidiopters or less, about 80 millidiopters or less, about 70millidiopters or less, about 60 millidiopters or less, or about 50millidiopters or less. As used herein, the optical distortion refers tothe maximum optical distortion measured on the respective surfaces.

In one or more embodiments, the third major surface or the fourth majorsurface of the second curved glass layer exhibits low membrane tensilestress. Membrane tensile stress can occur during cooling of curvedlayers and laminates. As the glass cools, the major surfaces and edgesurfaces (orthogonal to the major surfaces) can develop surfacecompression, which is counterbalanced by a central region exhibiting atensile stress. Bending or shaping can introduce additional surfacetension near the edge and causes the central tensile region to approachthe glass surface. Accordingly, membrane tensile stress is the tensilestress measured near the edge (e.g., about 10-25 mm from the edgesurface). In one or more embodiments, the membrane tensile stress at thethird major surface or the fourth major surface of the second curvedglass layer is less than about 7 MPa as measured by a surface stressmeter according to ASTM C1279. An example of such a surface stress meteris supplied by Strainoptic Technologies under the trademark GASP®(Grazing Angle Surface Polarimeter). In one or more embodiments, themembrane tensile stress at the third major surface or the fourth majorsurface of the second curved glass layer is about 6 MPa or less, about 5MPa or less, about 4 MPa or less, or about 3 MPa or less. In one or moreembodiments, the lower limit of membrane tensile stress is about 0.01MPa or about 0.1 MPa.

In one or more embodiments, the membrane compressive stress at the thirdmajor surface or the fourth major surface of the second curved glasslayer is less than about 7 MPa as measured by a surface stress meteraccording to ASTM C1279. A surface stress meter such as the surfacestress meter supplied by Strainoptic Technologies under the trademarkGASP® (Grazing Angle Surface Polarimeter) may be used. In one or moreembodiments, the membrane compressive stress at the third major surfaceor the fourth major surface of the second curved glass layer is about 6MPa or less, about 5 MPa or less, about 4 MPa or less, or about 3 MPa orless. In one or more embodiments, the lower limit of membranecompressive stress is about 0.01 MPa or about 0.1 MPa.

In one or more embodiments, the laminate 400 may have a thickness of6.85 mm or less, or 5.85 mm or less, where the thickness comprises thesum of thicknesses of the first curved glass layer, the second curvedglass layer, the interlayer (and any other layers). In variousembodiments, the laminate may have a thickness in the range of about 1.8mm to about 6.85 mm, or in the range of about 1.8 mm to about 5.85 mm,or in the range of about 1.8 mm to about 5.0 mm, or 2.1 mm to about 6.85mm, or in the range of about 2.1 mm to about 5.85 mm, or in the range ofabout 2.1 mm to about 5.0 mm, or in the range of about 2.4 mm to about6.85 mm, or in the range of about 2.4 mm to about 5.85 mm, or in therange of about 2.4 mm to about 5.0 mm, or in the range of about 3.4 mmto about 6.85 mm, or in the range of about 3.4 mm to about 5.85 mm, orin the range of about 3.4 mm to about 5.0 mm.

In one or more embodiments, the laminate 400 exhibits at least oneradius of curvature that is less than 1000 mm, or less than 750 mm, orless than 500 mm, or less than 300 mm. In one or more embodiments, thelaminate 300 exhibits at least one radius of curvature of about 10 m orless, or about 5 m or less along at least one axis. In one or moreembodiments, the laminate 400 may have a radius of curvature of 5 m orless along at least a first axis and along the second axis that isperpendicular to the first axis. In one or more embodiments, thelaminate may have a radius of curvature of 5 m or less along at least afirst axis and along the second axis that is not perpendicular to thefirst axis.

In one or more embodiments the first curved glass layer 410 isrelatively thin in comparison to the second curved glass layer 420. Inother words, the second curved glass layer has a thickness greater thanthe first curved glass layer. In one or more embodiments, the secondthickness is more than two times the first thickness. In one or moreembodiments, the second thickness is in the range from about 1.5 timesto about 10 times the first thickness (e.g., from about 1.75 times toabout 10 times, from about 2 times to about 10 times, from about 2.25times to about 10 times, from about 2.5 times to about 10 times, fromabout 2.75 times to about 10 times, from about 3 times to about 10times, from about 3.25 times to about 10 times, from about 3.5 times toabout 10 times, from about 3.75 times to about 10 times, from about 4times to about 10 times, from about 1.5 times to about 9 times, fromabout 1.5 times to about 8 times, from about 1.5 times to about 7.5times, from about 1.5 times to about 7 times, from about 1.5 times toabout 6.5 times, from about 1.5 times to about 6 times, from about 1.5times to about 5.5 times, from about 1.5 times to about 5 times, fromabout 1.5 times to about 4.5 times, from about 1.5 times to about 4times, from about 1.5 times to about 3.5 times, from about 2 times toabout 7 times, from about 2.5 times to about 6 times, from about 3 timesto about 6 times).

In one or more embodiments, the first curved glass layer 410 and thesecond curved glass layer 420 may have the same thickness. In one ormore specific embodiments, the second curved glass layer is more rigidor has a greater stiffness than the first curved glass layer, and invery specific embodiments, both the first curved glass layer and thesecond curved glass layer have a thickness in the range of 0.2 mm and1.6 mm.

In one or more embodiments, either one or both the first thickness 416and the second thickness 426 is less than 1.6 mm (e.g., 1.55 mm or less,1.5 mm or less, 1.45 mm or less, 1.4 mm or less, 1.35 mm or less, 1.3 mmor less, 1.25 mm or less, 1.2 mm or less, 1.15 mm or less, 1.1 mm orless, 1.05 mm or less, 1 mm or less, 0.95 mm or less, 0.9 mm or less,0.85 mm or less, 0.8 mm or less, 0.75 mm or less, 0.7 mm or less, 0.65mm or less, 0.6 mm or less, 0.55 mm or less, 0.5 mm or less, 0.45 mm orless, 0.4 mm or less, 0.35 mm or less, 0.3 mm or less, 0.25 mm or less,0.2 mm or less, 0.15 mm or less, or about 0.1 mm or less). The lowerlimit of thickness may be 0.1 mm, 0.2 mm or 0.3 mm. In some embodiments,either one or both the first thickness) and the second thickness is inthe range from about 0.1 mm to less than about 1.6 mm, from about 0.1 mmto about 1.5 mm, from about 0.1 mm to about 1.4 mm, from about 0.1 mm toabout 1.3 mm, from about 0.1 mm to about 1.2 mm, from about 0.1 mm toabout 1.1 mm, from about 0.1 mm to about 1 mm, from about 0.1 mm toabout 0.9 mm, from about 0.1 mm to about 0.8 mm, from about 0.1 mm toabout 0.7 mm, from about 0.1 mm, from about 0.2 mm to less than about1.6 mm, from about 0.3 mm to less than about 1.6 mm, from about 0.4 mmto less than about 1.6 mm, from about 0.5 mm to less than about 1.6 mm,from about 0.6 mm to less than about 1.6 mm, from about 0.7 mm to lessthan about 1.6 mm, from about 0.8 mm to less than about 1.6 mm, fromabout 0.9 mm to less than about 1.6 mm, or from about 1 mm to about 1.6mm.

In some embodiments, while one of the first thickness 416 and the secondthickness 426 is less than about 1.6 mm, the other of the firstthickness and the second thickness is about 1.6 mm or greater. In suchembodiments, first thickness and the second thickness differ from oneanother. For example, the while one of the first thickness 416 and thesecond thickness 426 is less than about 1.6 mm, the other of the firstthickness and the second thickness is about 1.7 mm or greater, about1.75 mm or greater, about 1.8 mm or greater, about 1.7 mm or greater,about 1.7 mm or greater, about 1.7 mm or greater, about 1.85 mm orgreater, about 1.9 mm or greater, about 1.95 mm or greater, about 2 mmor greater, about 2.1 mm or greater, about 2.2 mm or greater, about 2.3mm or greater, about 2.4 mm or greater, 2.5 mm or greater, 2.6 mm orgreater, 2.7 mm or greater, 2.8 mm or greater, 2.9 mm or greater, 3 mmor greater, 3.2 mm or greater, 3.4 mm or greater, 3.5 mm or greater, 3.6mm or greater, 3.8 mm or greater, 4 mm or greater, 4.2 mm or greater,4.4 mm or greater, 4.6 mm or greater, 4.8 mm or greater, 5 mm orgreater, 5.2 mm or greater, 5.4 mm or greater, 5.6 mm or greater, 5.8 mmor greater, or 6 mm or greater. In some embodiments the first thicknessor the second thickness is in a range from about 1.6 mm to about 6 mm,from about 1.7 mm to about 6 mm, from about 1.8 mm to about 6 mm, fromabout 1.9 mm to about 6 mm, from about 2 mm to about 6 mm, from about2.1 mm to about 6 mm, from about 2.2 mm to about 6 mm, from about 2.3 mmto about 6 mm, from about 2.4 mm to about 6 mm, from about 2.5 mm toabout 6 mm, from about 2.6 mm to about 6 mm, from about 2.8 mm to about6 mm, from about 3 mm to about 6 mm, from about 3.2 mm to about 6 mm,from about 3.4 mm to about 6 mm, from about 3.6 mm to about 6 mm, fromabout 3.8 mm to about 6 mm, from about 4 mm to about 6 mm, from about1.6 mm to about 5.8 mm, from about 1.6 mm to about 5.6 mm, from about1.6 mm to about 5.5 mm, from about 1.6 mm to about 5.4 mm, from about1.6 mm to about 5.2 mm, from about 1.6 mm to about 5 mm, from about 1.6mm to about 4.8 mm, from about 1.6 mm to about 4.6 mm, from about 1.6 mmto about 4.4 mm, from about 1.6 mm to about 4.2 mm, from about 1.6 mm toabout 4 mm, from about 3.8 mm to about 5.8 mm, from about 1.6 mm toabout 3.6 mm, from about 1.6 mm to about 3.4 mm, from about 1.6 mm toabout 3.2 mm, or from about 1.6 mm to about 3 mm.

In one or more embodiments, the laminate 400 is substantially free ofvisual distortion as measured by ASTM C1652/C1652M. In specificembodiments, the laminate, the first curved glass layer 410 and/or thesecond curved glass layer 420 are substantially free of wrinkles ordistortions that can be visually detected by the naked eye, according toASTM C1652/C1652M.

In one or more embodiments, the third major surface 422 or the fourthmajor surface 424 comprises a surface compressive stress of less than 3MPa as measured by a FSM surface stress meter. In some embodiments, thesecond curved glass layer is unstrengthened as will be described herein(but may optionally be annealed), and exhibits a surface compressivestress of less than about 3 MPa, or about 2.5 MPa or less, 2 MPa orless, 1.5 MPa or less, 1 MPa or less, or about 0.5 MPa or less, asmeasured on the third surface 422 or the fourth surface 424. In someembodiments, such surface compressive stress ranges are present on boththe third major surface and the fourth major surface.

In one or more embodiments, either one or both the first curved glasslayer 410 and the second curved glass layer 420 is strengthened, asdescribed herein. In one or more embodiments, the first curved glasslayer comprises a strengthened glass article according to theembodiments described herein, while the second curved glass layer is notstrengthened. In one or more embodiments, the first curved glass layercomprises a strengthened glass article according to the embodimentsdescribed herein, while the second curved glass layer is annealed. Inone or more embodiments, the first curved glass layer is strengthenedchemically, mechanically and/or thermally, while the second curved glasslayer is strengthened in different manner than the first curved glasslayer (chemically, mechanically and/or thermally). In one or moreembodiments, the first curved glass layer is strengthened chemically,mechanically and/or thermally, while the second curved glass layer isstrengthened in the same manner than the first curved glass layer(chemically, mechanically and/or thermally). In one or more embodiments,the first curved glass layer is strengthened and the second curved glasslayer is not strengthened. In one or more embodiments, the first curvedglass layer is strengthened and the second curved glass layer isannealed. In one or more embodiments, both the first curved glass layerand the second curved glass layer are strengthened (either in the samemanner or differently from one another). In one or more embodiments, thesecond curved glass layer comprises a soda lime silicate glass, whilethe first glass substrate may be characterized as including one or moreembodiments of the glass article described herein.

In one or more embodiments, the first curved glass layer 410 comprises afirst length and a first width wherein, either one of or both the firstlength and the first width is about 0.25 meters or greater. In one ormore embodiments, the second curved glass layer comprises a secondlength that is within 5% of the first length, and a second width that iswithin 5% of the first width. In one or more embodiments, the laminate400 may be described as curved or complexly curved, as defined herein.

In one or more embodiments, the laminate 400 is automotive glazing orarchitectural glazing.

Another aspect of this disclosure includes a vehicle including a bodydefining an interior and an opening in communication with the interior;and laminate 400 disposed in the opening. In such embodiments, thelaminate 400 may be complexly curved or simply curved, as definedherein.

Another aspect of this disclosure pertains to a laminate 500 in which afirst glass layer comprising an embodiment of a glass article describedherein may be cold-formed (with an intervening interlayer) to a secondglass layer. In an exemplary cold-formed laminate 500 shown in FIGS.7-8, a first glass layer 510 (including a glass article according to oneor more embodiments) is laminated to a relatively thicker and curvedsecond glass layer 530. In FIG. 7, second glass layer 530 includes afirst surface 532 and a second surface 534 in contact with an interlayer520, and the first glass layer 510 includes a third surface 512 incontact with the interlayer 520 and a fourth surface 514. An indicatorof a cold-formed laminate is the fourth surface 514 has a greatersurface CS than the third surface 512. Accordingly, a cold-formedlaminate can comprise a high compressive stress level on fourth surface514 making this surface more resistant to fracture.

In one or more embodiments, prior to the cold-forming process, therespective compressive stresses in the third surface 512 and fourthsurface 514 are substantially equal. In one or more embodiments in whichthe first glass layer is unstrengthened, the third surface 512 and thefourth surface 514 exhibit no appreciable compressive stress, prior tocold-forming. In one or more embodiments in which the first glass layer510 is strengthened (as described herein), the third surface 512 and thefourth surface 514 exhibit substantially equal compressive stress withrespect to one another, prior to cold-forming. In one or moreembodiments, after cold-forming, the compressive stress on the fourthsurface 514 increases (i.e., the compressive stress on the fourthsurface 514 is greater after cold-forming than before cold-forming).Without being bound by theory, the cold-forming process increases thecompressive stress of the glass layer being shaped (i.e., the firstglass layer) to compensate for tensile stresses imparted during bendingand/or forming operations. In one or more embodiments, the cold-formingprocess causes the third surface of that glass layer (i.e., the thirdsurface 512) to experience tensile stresses, while the fourth surface ofthe glass layer (i.e., the fourth surface 514) experiences compressivestresses.

When a strengthened first glass layer 510 is utilized, the third andfourth surfaces (512, 514) are already under compressive stress, andthus the third surface 512 can experience greater tensile stress. Thisallows for the strengthened first glass layer 510 to conform to moretightly curved surfaces.

In one or more embodiments, the first glass layer 510 has a thicknessless than the second glass layer 530. This thickness differential meansthe first glass layer 510 is more flexible to conform to the shape ofthe second glass layer 530. Moreover, a thinner first glass layer 510may deform more readily to compensate for shape mismatches and gapscreated by the shape of the second glass layer 530. In one or moreembodiments, a thin and strengthened first glass layer 510 exhibitsgreater flexibility especially during cold-forming. In one or moreembodiments, the first glass layer 510 conforms to the second glasslayer 530 to provide a substantially uniform distance between the secondsurface 534 and the third surface 512, which is filled by theinterlayer.

In some non-limiting embodiments, the cold-formed laminate 500 may beformed using an exemplary cold forming process that is performed at atemperature at or just above the softening temperature of the interlayermaterial (e.g., 520) (e.g., about 100° C. to about 120° C.), that is, ata temperature less than the softening temperature of the respectiveglass layers. In one embodiment as shown in FIG. 7, the cold-formedlaminate may be formed by: placing an interlayer between the secondglass layer (which is curved) and a first glass layer (which may beflat) to form a stack; applying pressure to the stack to press thesecond glass layer against the interlayer layer which is pressed againstthe first glass layer; and heating the stack to a temperature below 400°C. to form the cold-formed laminate in which the second glass layerconforms in shape to the first glass layer. Such a process can occurusing a vacuum bag or ring in an autoclave or another suitableapparatus. The stress of an exemplary first glass layer 410 may changefrom substantially symmetrical to asymmetrical according to someembodiments of the present disclosure.

As used herein, “flat” and “planar” are used interchangeably and mean ashape having curvature less than a curvature at which lamination defectsare created due to curvature mismatch, when such a flat layer iscold-formed to another layer (i.e., a radius of curvature of greaterthan or equal to about 3 meters, greater than or equal to about 4 metersor greater than or equal to about 5 meters). A flat layer has theforegoing shape when placed on a surface. As used herein, a “simplecurve” or “simply curved” means a non-planar shape having curvaturealong one axis (forming a cylindrical shape or bend). As used herein“complex curve” and “complexly curved” mean a non-planar shape havingcurvature along two orthogonal axes that are different from one another.Examples of complexly curved shapes include having simple or compoundcurves, also referred to as non-developable shapes, which include butare not limited to spherical, aspherical, and toroidal. The complexlycurved shapes may also include segments or portions of such surfaces, orbe comprised of a combination of such curves and surfaces. In one ormore embodiments, a laminate may have a simple curve or complex curve.In one or more embodiments the first glass layer, the second glasslayer, the laminate or a combination thereof may have a simple curve orcomplexly curved shape and may be cold-formed. As a non-limitingexample, the simply-curved laminate may have length and width dimensionsof 0.5 m by 1.0 m and a radius of curvature of 2 to 5 m along a singleaxis.

A complexly curved laminate according to one or more embodiments mayhave a distinct radius of curvature in two independent directions.According to one or more embodiments, complexly curved laminates maythus be characterized as having “cross curvature,” where the laminate iscurved along an axis (i.e., a first axis) that is parallel to a givendimension and also curved along an axis (i.e., a second axis) that isperpendicular to the same dimension. The curvature of the laminate canbe even more complex when a significant minimum radius is combined witha significant cross curvature, and/or depth of bend. Some laminates mayalso include bending along axes that are not perpendicular to oneanother. As a non-limiting example, the complexly-curved laminate mayhave length and width dimensions of 0.5 m by 1.0 m and a radius ofcurvature of 2 to 2.5 m along the minor axis, and a radius of curvatureof 4 to 5 m along the major axis. In one or more embodiments, thecomplexly-curved laminate may have a radius of curvature of 5 m or lessalong at least one axis. In one or more embodiments, thecomplexly-curved laminate may have a radius of curvature of 5 m or lessalong at least a first axis and along the second axis that isperpendicular to the first axis. In one or more embodiments, thecomplexly-curved laminate may have a radius of curvature of 5 m or lessalong at least a first axis and along the second axis that is notperpendicular to the first axis.

As shown in FIG. 8, first glass layer 410 may be simply-curved orcomplexly-curved and have at least one concave surface (e.g., surface514) providing a fourth surface of the laminate and at least one convexsurface (e.g., surface 512) to provide a third surface of the laminateopposite the first surface with a thickness therebetween. In thecold-forming embodiment, the second glass sheet 530 may becomplexly-curved and have at least one concave surface (e.g., secondsurface 534) and at least one convex surface (e.g., first surface 532)with a thickness therebetween.

In one or more embodiments, one or more of interlayer 520, first glasslayer 510, and second glass layer 530 comprise a first edge (e.g., 535)with a first thickness and a second edge (e.g., 537) opposite the firstedge with a second thickness greater than the first thickness.

As otherwise described herein, one aspect of this disclosure pertains toa vehicle that includes the glass articles or laminates describedherein. For example, as shown in FIG. 9 shows a vehicle 600 comprising abody 610 defining an interior, at least one opening 620 in communicationwith the interior, and a window disposed in the opening, wherein thewindow comprises a laminate or a glass article 630, according to one ormore embodiments described herein. The laminate or glass article 630 mayform the sidelights, windshields, rear windows, windows, rearviewmirrors, and sunroofs in the vehicle. In some embodiments, the laminateor glass article 630 may form an interior partition (not shown) withinthe interior of the vehicle, or may be disposed on an exterior surfaceof the vehicle and form an engine block cover, headlight cover,taillight cover, door panel cover, or pillar cover. In one or moreembodiments, the vehicle may include an interior surface (not shown, butmay include door trim, seat backs, door panels, dashboards, centerconsoles, floor boards, rear view mirror and pillars), and the laminateor glass article 630 described herein is disposed on the interiorsurface. In one or more embodiment, the interior surface includes adisplay and the glass layer is disposed over the display. As usedherein, vehicle includes automobiles, rolling stock, locomotive, boats,ships, and airplanes, helicopters, drones, space craft and the like.

Another aspect of this disclosure pertains to an architecturalapplication that includes the glass articles or laminates describedherein. In some embodiments, the architectural application includesbalustrades, stairs, decorative panels or covering for walls, acousticpanels or coverings, columns, partitions, elevator cabs, householdappliances, windows, furniture, and other applications, formed at leastpartially using a laminate or glass article according to one or moreembodiments.

In one or more embodiments, the portion of the laminate including theglass article is positioned within a vehicle or architecturalapplication such that the glass article faces the interior of thevehicle or the interior of a building or room, such that the glassarticle is adjacent to the interior (and the other glass ply is adjacentthe exterior). In some embodiments, the glass article of the laminate isin direct contact with the interior (i.e., the surface of the glassarticle facing the interior is bare and is free of any coatings).

In one or more embodiments, the portion of the laminate including theglass article is positioned within a vehicle or architecturalapplication such that the glass article faces the exterior of thevehicle or the exterior of a building or room, such that the glassarticle is adjacent to the exterior (and the other glass ply is adjacentthe interior). In some embodiments, the glass article of the laminate isin direct contact with the exterior (i.e., the surface of the glassarticle facing the exterior is bare and is free of any coatings).

In one or more embodiments, the glass articles and/or laminatesdescribed herein may have added functionality in terms of incorporatingdisplay aspects (e.g., heads up display, projection surfaces, and thelike), antennas, solar insulation, acoustic performance (e.g., sounddampening), anti-glare performance, anti-reflective performance,scratch-resistance and the like. Such functionality may be imparted bycoatings or layers applied to the exposed surfaces of the laminate or tointerior (unexposed) surfaces (e.g., between the glass layers or betweena glass layer and an interlayer). In some embodiments, the laminate mayhave a thickness or configuration to enable improved optical performancewhen the laminate is used as a heads-up display (e.g., by incorporatinga wedged shaped polymer interlayer between the glass layers or byshaping one of the glass layers to have a wedged shape). In one or moreembodiments, the laminate includes a textured surface that providesanti-glare functionality and such textured surface may be disposed on anexposed surface or an interior surface that is unexposed. In one or moreembodiments, the laminate may include an anti-reflective coating, ascratch-resistant coating or a combination thereof disposed on anexposed surface. In one or more embodiments, the laminate may include anantenna disposed on an exposed surface, and interior surface that is notexposed or embedded in any one of the glass layers. In one or moreembodiments, the interlayer can be modified to have one or more of thefollowing properties: ultraviolet (UV) absorption, Infrared (IR)absorption, IR reflection, acoustic control/dampening, adhesionpromotion, and tint. The interlayer can be modified by a suitableadditive such as a dye, a pigment, dopants, etc. to impart the desiredproperty.

In a first example (referring to FIG. 5, 7 or 9), the laminate includesa first glass layer 310, 410, 510 comprising a glass article accordingto one or more embodiments, a second glass layer 330, 430, 520comprising a SLG article, and an interlayer 320, 420, 530 comprisingPVB. In one or more embodiments, the glass article used in the firstlayer has a thickness of about 1 mm or less. In some embodiments, theglass article in the first layer is chemically strengthened. In someembodiments, the SLG article used in the second glass layer is annealed.In one or more embodiments, the laminate is positioned in a vehicle suchthat the first glass layer (comprising the glass article according toone or more embodiments) faces the interior of the vehicle.

In a second example (referring to FIG. 5, 7 or 9), the laminate includesa first glass layer 310, 410, 510 comprising a glass article accordingto one or more embodiments, a second glass layer 330, 430, 520comprising a SLG article, and an interlayer 320, 420, 530 comprisingPVB. In one or more embodiments, the glass article used in the firstlayer has a thickness of about 1 mm or less. In some embodiments, theglass article in the first layer is thermally strengthened. In someembodiments, the SLG article used in the second glass layer is annealed.In one or more embodiments, the laminate is positioned in a vehicle suchthat the first glass layer (comprising the glass article according toone or more embodiments) faces the interior of the vehicle.

Another aspect of this disclosure pertains to a method for forming thelaminate including a glass article as described herein. In one or moreembodiments, the method includes stacking a first glass articleaccording to any one or more embodiments described herein, and a secondglass article that differs from the first glass article to form a stack,wherein the first glass layer comprises a first surface and an secondsurface that opposes the first surface, and the second glass articlecomprises a third surface and a fourth surface that opposes the thirdsurface, and wherein the second surface is adjacent to the thirdsurface. In one or more embodiments, the first glass article and thesecond glass article differ in any one or more of composition,thickness, strengthening level, and forming method. In one or moreembodiments, the method includes placing the stack on a mold, heatingthe stack to a temperature at which the second glass article exhibits aviscosity of 10¹⁰ poise to form a shaped stack, and placing aninterlayer between the first glass article and the second glass layer.In one or more embodiments, the shaped stack comprises a gap between thesecond surface and the third surface having a maximum distance of about10 mm or less, 5 mm or less, or about 3 mm or less. In one or moreembodiments, the second glass article is a SLG article. In one or moreembodiments, the first glass article has a thickness of less than 1.6 mm(e.g., 1.5 mm or less, 1 mm or less, or 0.7 mm or less) and the secondglass article has a thickness of 1.6 mm or greater (e.g., 1.8 mm ormore, 2.0 mm or greater or 2.1 mm or greater). In one or moreembodiments, the first glass article is fusion formed and the secondglass article is float formed.

Another aspect of this disclosure pertains to devices that include theglass articles or laminates described herein. For example, the devicesmay include any device including a display. In one or more embodimentsthe devices are electronic devices, which can include mobile devicessuch as mobile phones, laptops, tablets, mp3 players, navigation devicesand the like, or stationary devices such as computers, electronicdisplays, in vehicle information/entertainment systems, billboards,point of sale systems, navigation systems, and the like). An exemplaryan electronic device includes a housing having front, back, and sidesurfaces; electrical components that are at least partially inside orentirely within the housing and including at least a controller, amemory, and a display at or adjacent to the front surface of thehousing. The glass articles or laminates described herein may bedisposed at or over the front surface of the housing such that it isover the display (i.e., forming a cover over the display). In someembodiments, the glass article or laminate may be used as a back cover.

EXAMPLES

Various embodiments will be further clarified by the following examples.

Examples 1-67

Examples 1-67 are exemplary glass compositions according to one or moreembodiments of this disclosure. The glass compositions (in mol %) ofExamples 1-67 are provided in Table 1. Table 1 also includes informationrelated to the density at 20° C., strain point temperature (as measuredby beam bending viscometer), annealing point temperature (as measured bybeam bending viscometer), softening point temperature (as measured byfiber elongation), CTE, Stress Optical Coefficient, refractive index,T₂₀₀, T₃₅₀₀₀, T₂₀₀₀₀₀, liquidus temperature, liquidus viscosity, zirconbreakdown temperature, zircon breakdown viscosity, and other attributes.

Examples 1-51, and 53-58, and 61 were fusion formed into glass articleshaving a thickness 1 mm or 0.55 mm as shown in Table 1, annealed andthen chemically strengthened, as provided in Table 1. The resultingsurface CS (MPa) and DOC (micrometers) values of the strengthened glassarticles after being chemically strengthened are also provided inTable 1. The DOC values were measured using FSM.

TABLE 1 Examples 1-67. Examples 1 2 3 4 5 Analyzed mol % 177BUP 177BUT177BUU 177CLQ 177CLR SiO₂ 73.13 73.02 72.51 70.48 70.70 Al₂O₃ 9.95 9.169.05 8.97 9.00 P₂O₅ 0.00 0.00 0.00 0.00 0.00 Na₂O 13.13 13.02 14.3215.50 16.32 K₂O 1.94 2.64 1.87 2.93 2.90 MgO 0.05 0.05 0.05 0.05 0.03ZnO 0.00 0.00 0.00 0.00 0.00 CaO 1.61 1.91 2.00 1.97 0.95 SnO₂ 0.20 0.200.19 0.10 0.10 R₂O—Al₂O₃ 5.11 6.50 7.14 9.46 10.22 R₂O:Al₂O₃ 1.51 1.711.79 2.06 2.14 Density (g/cm³) 2.428 2.434 2.439 2.453 2.447 StrainPoint (° C.) 544 525 522 502 488 Anneal Point (° C.) 596 574 569 547 533Softening Point (° C.) 839.1 808.5 795.5 756.3 745 [Anneal Point (°C.) + Softening 718 691 682 652 639 Point (° C.)]/2 Coefficient ofThermal 82.6 85.4 86.7 95.5 96.2 Expansion × 10⁻⁷ (1/° C.) StressOptical Coefficient 3.015 2.991 2.957 2.847 2.857 (nm/mm/MPa) RefractiveIndex 1.4993 1.5005 1.5013 1.5035 1.5019 200 Poise Temperature (° C.)1733 1689 1660 1580 1577 35000 Poise Temperature (° C.) 1169 1135 11171057 1050 200000 Poise Temperature (° C.) 1055 1024 1010 955 946Liquidus Temperature (° C.) 875 Liquidus Viscosity (kP) 1075 ZirconBreakdown Temperature (° C.) 1155 Zircon Breakdown Viscosity (kP) 9.0T200P − T35kP (° C.) 564 554 543 523 527 Anneal Point (° C.) − Softening−243.1 −234.5 −226.5 −209.3 −212 Point (° C. [Anneal Point (° C.) +Softening −1016 −998 −978 −928 −938 Point (° C.)]/2 − T²⁰⁰ [Anneal Point(° C.) + Softening −452 −444 −435 −406 −411 Point (° C.)]/2 − T³⁵⁰⁰⁰Ion-Exchange of Annealed parts in refined KNO₃ at 410° C. for 4 hoursThickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 673 564 586 639 565DOC (microns) 20 38 33 37 43 Examples 6 7 8 9 10 Analyzed mol % 177CLS177CLT 177CLU 177CLV 177CMC SiO₂ 70.85 69.62 69.76 70.04 70.55 Al₂O₃8.99 8.94 9.07 8.88 9.33 P₂O₅ 0.00 0.00 0.00 0.00 0.00 Na₂O 14.22 15.9117.21 14.10 14.02 K₂O 2.85 2.91 2.88 2.88 2.77 MgO 0.07 0.06 0.02 0.090.07 ZnO 0.00 0.00 0.00 0.00 0.00 CaO 2.93 2.46 0.95 3.91 3.15 SnO₂ 0.100.10 0.10 0.10 0.10 R₂O—Al₂O₃ 8.08 9.88 11.02 8.11 7.46 R₂O:Al₂O₃ 1.902.10 2.22 1.91 1.80 Density (g/cm³) 2.453 2.461 2.454 2.467 2.453 StrainPoint (° C.) 516 499 485 519 525 Anneal Point (° C.) 562 544 529 564 570Softening Point (° C.) 776.4 749.6 736.6 772.6 787 [Anneal Point (°C.) + Softening 669 647 633 668 679 Point (° C.)]/2 Coefficient ofThermal 91.7 97 99.7 93.4 91.2 Expansion × 10⁻⁷ (1/° C.) Stress OpticalCoefficient 2.869 2.851 2.816 2.86 2.9 (nm/mm/MPa) Refractive Index1.5044 1.5056 1.5033 1.5080 1.5000 200 Poise Temperature (° C.) 16001542 1543 1558 1615 35000 Poise Temperature (° C.) 1079 1041 1030 10631091 200000 Poise Temperature (° C.) 976 940 927 964 988 LiquidusTemperature (° C.) 895 850 820 910 Liquidus Viscosity (kP) 1067 13731976 628 Zircon Breakdown Temperature (° C.) 1185 1155 1160 1155 ZirconBreakdown Viscosity (kP) 8.2 7.2 6.1 9.3 T200P − T35kP (° C.) 521 501512 495 524 Anneal Point (° C.) − Softening −214.4 −205.6 −207.6 −208.6−217 Point (° C. [Anneal Point (° C.) + Softening −931 −895 −910 −889−937 Point (° C.)]/2 − T²⁰⁰ [Anneal Point (° C.) −410 −394 −398 −395−413 Point (° C.)/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refinedKNO₃ at 410° C. for 4 hours Thickness (mm) 1.0 1.0 1.0 1.0 1.0 SurfaceCS (MPa) 700 641 547 743 737 DOC (microns) 31 37 43 29 31 Examples 11 1213 14 15 Analyzed mol % 177CMD 177CME 177CMF 177CMG 177CMH SiO₂ 69.6569.04 70.23 69.49 69.31 Al₂O₃ 9.49 9.76 9.31 9.61 9.96 P₂O₅ 0.00 0.000.00 0.00 0.00 Na₂O 14.38 14.44 14.50 14.87 14.79 K₂O 2.88 2.90 2.872.92 2.86 MgO 0.07 0.08 0.07 0.06 0.07 ZnO 0.00 0.00 0.00 0.00 0.00 CaO3.43 3.69 2.92 2.95 2.92 SnO₂ 0.10 0.10 0.10 0.10 0.10 R₂O—Al₂O₃ 7.767.58 8.06 8.18 7.69 R₂O:Al₂O₃ 1.82 1.78 1.87 1.85 1.77 Density (g/cm³)2.462 2.466 2.455 2.46 2.46 Strain Point (° C.) 525 525 518 518 523Anneal Point (° C.) 569 570 563 563 568 Softening Point (° C.) 781.6783.7 777.7 775.8 783.4 [Anneal Point (° C.) + Softening 675 677 670 669676 Point (° C.)]/2 Coefficient of Thermal 93.3 93.4 93.1 94.2 94Expansion × 10⁻⁷ (1/° C.) Stress Optical Coefficient 2.86 2.83 2.8852.876 2.88 (nm/mm/MPa) Refractive Index 1.5000 1.5000 1.5000 1.50001.5000 200 Poise Temperature (° C.) 1598 1586 1595 1592 1594 35000 PoiseTemperature (° C.) 1082 1080 1076 1073 1081 200000 Poise Temperature (°C.) 979 978 974 971 978 Liquidus Temperature (° C.) Liquidus Viscosity(kP) Zircon Breakdown Temperature (° C.) Zircon Breakdown Viscosity (kP)T200P − T35kP (° C.) 516 506 518 518 513 Anneal Point (° C.) − Softening−212.6 −213.7 −214.7 −212.8 −215.4 Point (° C. [Anneal Point (° C.) +Softening −922 −909 −924 −922 −918 Point (° C.)]/2 − T²⁰⁰ [Anneal Point(° C.) + Softening −406 −403 −406 −404 −406 Point (° C.)]/2 − T³⁵⁰⁰⁰Ion-Exchange of Annealed parts in refined KNO₃ at 410° C. for 4 hoursThickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 748 765 703 738 747DOC (microns) 31 31 34 31 33 Examples 16 17 18 19 20 Analyzed mol %177CMI 177CMJ 177CMK 177CML 177CMM SiO₂ 67.72 67.19 66.23 66.77 65.69Al₂O₃ 11.04 11.25 11.75 11.47 11.92 P₂O₅ 0.00 0.00 0.00 0.00 0.00 Na₂O16.24 16.30 16.24 16.25 16.32 K₂O 2.91 2.92 2.90 2.91 2.94 MgO 0.05 0.060.06 0.06 0.07 ZnO 0.00 0.00 0.00 0.00 0.00 CaO 1.95 2.19 2.71 2.44 2.96SnO₂ 0.10 0.10 0.10 0.10 0.10 R₂O—Al₂O₃ 8.11 7.97 7.39 7.70 7.34R₂O:Al₂O₃ 1.74 1.71 1.63 1.67 1.62 Density (g/cm³) 2.464 2.468 2.4742.472 2.478 Strain Point (° C.) 520 523 532 528 534 Anneal Point (° C.)564 568 576 572 578 Softening Point (° C.) 779.7 783.4 791.5 786.2 791.4[Anneal Point (° C.) + Softening 672 676 684 679 685 Point (° C.)]/2Coefficient of Thermal 97.4 97.6 97.9 97.6 99 Expansion × 10⁻⁷ (1/° C.)Stress Optical Coefficient 2.878 2.849 2.829 2.823 2.837 (nm/mm/MPa)Refractive Index 1.5056 1.5067 1.5082 1.5073 1.5091 200 PoiseTemperature (° C.) 1598 1587 1599 1591 35000 Poise Temperature (° C.)1082 1082 1091 1090 200000 Poise Temperature (° C.) 976 980 989 988Liquidus Temperature (° C.) Liquidus Viscosity (kP) Zircon BreakdownTemperature (° C.) Zircon Breakdown Viscosity (kP) T200P − T35kP (° C.)515 504 508 0 501 Anneal Point (° C.) − Softening −215.7 −215.4 −215.5−214.2 −213.4 Point (° C. [Anneal Point (° C.) + Softening −926 −911−915 −906 Point (° C.)]/2 − T²⁰⁰ [Anneal Point (° C.) + Softening −410−407 −407 −405 Point (° C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed partsin refined KNO₃ at 410° C. for 4 hours Thickness (mm) 1.0 1.0 1.0 1.01.0 Surface CS (MPa) 753 747 809 774 804 DOC (microns) 37 38 35 35 35Ion-Exchange of Annealed parts in refined KNO₃ at 410° C. for 6 hoursThickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 727 774 814 774 806DOC (microns) 45 43 42 43 43 Examples 21 22 23 24 25 Analyzed mol %177CMN 177CNK 177CNL 177CNM 177CNN SiO₂ 65.63 68.04 67.43 66.97 66.55Al₂O₃ 12.26 9.01 9.29 9.55 9.73 P₂O₅ 0.00 0.00 0.00 0.00 0.00 Na₂O 15.9016.03 16.08 16.01 16.09 K₂O 2.83 2.86 2.87 2.86 2.87 MgO 0.08 2.02 2.032.04 1.99 ZnO 0.00 0.00 0.00 0.00 0.00 CaO 3.19 1.95 2.20 2.46 2.67 SnO₂0.10 0.10 0.10 0.10 0.10 R₂O—Al₂O₃ 6.48 9.87 9.67 9.32 9.23 R₂O:Al₂O₃1.53 2.10 2.04 1.98 1.95 Density (g/cm³) 2.478 2.466 2.47 2.472 2.475Strain Point (° C.) 544 505 510 513 515 Anneal Point (° C.) 589 550 554558 559 Softening Point (° C.) 804 762.7 763.1 766.3 766.4 [Anneal Point(° C.) + Softening 697 656 659 662 663 Point (° C.)]/2 Coefficient ofThermal 97.1 98.8 98.1 98.4 99.3 Expansion × 10⁻⁷ (1/° C.) StressOptical Coefficient 2.84 2.832 2.825 2.855 2.829 (nm/mm/MPa) RefractiveIndex 1.5098 1.5065 1.5074 1.5078 1.5085 200 Poise Temperature (° C.)1602 1545 1541 1540 1538 35000 Poise Temperature (° C.) 1104 1048 10481052 1053 200000 Poise Temperature (° C.) 1002 950 951 955 956 LiquidusTemperature (° C.) 830 830 830 860 Liquidus Viscosity (kP) 3374 36293861 1823 Zircon Breakdown Temperature (° C.) 1115 1120 1105 1080 ZirconBreakdown Viscosity (kP) 13.0 12.0 15.7 23.0 T200P − T35kP (° C.) 497497 493 488 485 Anneal Point (° C.) − Softening −215 −212.7 −209.1−208.3 −207.4 Point (° C. [Anneal Point (° C.) + Softening −905 −889−882 −878 −876 Point (° C.)]/2 − T²⁰⁰ [Anneal Point (° C.) + Softening−408 −392 −390 −390 −391 Point (° C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange ofAnnealed parts in refined KNO₃ at 410° C. for 4 hours Thickness (mm) 1.01.0 1.0 1.0 1.0 Surface CS (MPa) 854 705 732 766 766 DOC (microns) 34 3634 33 33 Ion-Exchange of Annealed parts in refined KNO₃ at 410° C. for 6hours Thickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 848 690 735757 761 DOC (microns) 41 42 41 39 39 Examples 26 27 28 29 30 Analyzedmol % 177CNO 177CNP 177CPV 177CPW 177CPX SiO₂ 66.06 65.42 67.47 66.4365.44 Al₂O₃ 9.94 10.15 7.89 8.06 8.26 P₂O₅ 0.00 0.00 0.00 0.00 0.00 Na₂O16.07 16.23 16.25 16.70 16.50 K₂O 2.88 2.92 2.84 3.02 3.02 MgO 2.01 1.995.40 5.65 6.64 ZnO 0.00 0.00 0.00 0.00 0.00 CaO 2.94 3.20 0.04 0.04 0.04SnO₂ 0.10 0.10 0.11 0.11 0.11 R₂O—Al₂O₃ 9.01 8.99 11.20 11.66 11.25R₂O:Al₂O₃ 1.91 1.89 2.42 2.45 2.36 Density (g/cm³) 2.48 2.484 2.4512.456 2.461 Strain Point (° C.) 519 518 501 505 509 Anneal Point (° C.)563 563 548 552 556 Softening Point (° C.) 770.7 769.8 765.2 766.4 771.5[Anneal Point (° C.) + Softening 667 666 657 659 664 Point (° C.)]/2Coefficient of Thermal 99.2 100.6 100.5 100.4 101.5 Expansion × 10⁻⁷(1/° C.) Stress Optical Coefficient 2.808 2.798 2.864 2.866 2.852(nm/mm/MPa) Refractive Index 1.5097 1.5107 1.5043 1.5070 1.5071 200Poise Temperature (° C.) 1531 1527 1525 1523 1521 35000 PoiseTemperature (° C.) 1053 1051 1049 1055 1056 200000 Poise Temperature (°C.) 957 955 952 958 963 Liquidus Temperature (° C.) 850 <780 <790 825Liquidus Viscosity (kP) 2235 >16869 >20613 3294 Zircon BreakdownTemperature (° C.) 1090 1105 1105 1055 Zircon Breakdown Viscosity (kP)19.8 15 16 35 T200P − T35kP (° C.) 478 476 476 468 465 Anneal Point (°C.) − Softening −207.7 −206.8 −217.2 −214.4 −215.5 Point (° C. [AnnealPoint (° C.) + Softening −865 −860 −869 −864 −857 Point (° C.)]/2 − T²⁰⁰[Anneal Point (° C.) + Softening −387 −384 −392 −396 −392 Point (°C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃ at 410°C. for 4 hours Thickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 855839 684 757 771 DOC (microns) 30 30 42 38 40 Ion-Exchange of Annealedparts in refined KNO₃ at 410° C. for 6 hours Thickness (mm) 1.0 1.0 1.01.0 1.0 Surface CS (MPa) 859 829 675 725 771 DOC (microns) 35 38 49 4647 Examples 31 32 33 34 35 Analyzed mol % 177CPY 177CPZ 177CQA 177CPD177CPE SiO₂ 66.91 66.72 65.80 67.73 67.41 Al₂O₃ 8.53 8.64 8.87 9.00 8.95P₂O₅ 0.00 0.00 0.00 0.23 0.47 Na₂O 16.84 16.69 16.56 16.10 16.21 K₂O3.04 2.95 2.96 2.89 2.90 MgO 0.01 0.01 0.01 2.00 1.99 ZnO 4.54 4.85 5.660.00 0.00 CaO 0.04 0.04 0.04 1.95 1.97 SnO₂ 0.10 0.10 0.10 0.10 0.10R₂O—Al₂O₃ 11.34 10.99 10.66 9.98 10.16 R₂O:Al₂O₃ 2.33 2.27 2.20 2.112.14 Density (g/cm³) 2.524 2.531 2.545 2.465 2.464 Strain Point (° C.)498 503 510 503 503 Anneal Point (° C.) 544 550 556 549 549 SofteningPoint (° C.) 755.6 760.1 761.9 759.2 759.7 [Anneal Point (° C.) +Softening 650 655 659 654 654 Point (° C.)]/2 Coefficient of Thermal99.8 101 101.4 98.3 98.8 Expansion × 10⁻⁷ (1/° C.) Stress OpticalCoefficient 2.982 3.08 3.113 2.828 2.838 (nm/mm/MPa) Refractive Index1.5104 1.5135 1.5115 1.5061 1.5054 200 Poise Temperature (° C.) 15161511 1512 1556 1541 35000 Poise Temperature (° C.) 1034 1040 1043 10531047 200000 Poise Temperature (° C.) 940 945 952 955 949 LiquidusTemperature (° C.) 815 840 805 Liquidus Viscosity (kP) 4733 3273 7812Zircon Breakdown Temperature (° C.) 1100 1090 1060 Zircon BreakdownViscosity (kP) 13 16 26 T200P − T35kP (° C.) 481 471 470 503 494 AnnealPoint (° C.) − Softening −211.6 −210.1 −205.9 −210.2 −210.7 Point (° C.[Anneal Point (° C.) + Softening −866 −856 −853 −901 −887 Point (°C.)]/2 − T²⁰⁰ [Anneal Point (° C.) + Softening −385 −384 −384 −398 −393Point (° C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃at 410° C. for 4 hours Thickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS(MPa) 701 694 777 704 683 DOC (microns) 44 42 43 37 39 Ion-Exchange ofAnnealed parts in refined KNO₃ at 410° C. for 6 hours Thickness (mm) 1.01.0 1.0 1.0 1.0 Surface CS (MPa) 660 670 746 694 650 DOC (microns) 53 5249 44 47 Examples 36 37 38 39 40 Analyzed mol % 177CPF 177CPG 177CPH177CPI 177CPJ SiO₂ 67.00 66.87 66.54 66.18 67.30 Al₂O₃ 8.98 8.96 8.948.99 9.03 P₂O₅ 0.68 0.91 1.17 1.44 0.24 Na₂O 16.35 16.31 16.38 16.4116.34 K₂O 2.93 2.90 2.91 2.91 2.92 MgO 1.99 1.99 1.99 1.99 0.01 ZnO 0.000.00 0.00 0.01 4.04 CaO 1.96 1.96 1.97 1.96 0.02 SnO₂ 0.10 0.10 0.100.10 0.10 R₂O—Al₂O₃ 10.31 10.25 10.36 10.34 10.23 R₂O:Al₂O₃ 2.15 2.142.16 2.15 2.13 Density (g/cm³) 2.465 2.464 2.465 2.468 2.516 StrainPoint (° C.) 499 499 499 499 507 Anneal Point (° C.) 545 545 545 545 554Softening Point (° C.) 758.4 765.3 766.5 772 768.9 [Anneal Point (°C.) + Softening 652 655 656 659 661 Point (° C.)]/2 Coefficient ofThermal 99.6 99.8 99.6 100.3 98.5 Expansion × 10⁻⁷ (1/° C.) StressOptical Coefficient 2.826 2.823 2.811 2.826 3.07 (nm/mm/MPa) RefractiveIndex 1.5051 1.5046 1.5045 1.5048 1.5083 200 Poise Temperature (° C.)1530 1535 1539 1532 1543 35000 Poise Temperature (° C.) 1047 1049 10481052 1056 200000 Poise Temperature (° C.) 949 951 950 954 960 LiquidusTemperature (° C.) 1070 1070 860 Liquidus Viscosity (kP) 25 25 1688Zircon Breakdown Temperature (° C.) 1135 1105 Zircon Breakdown Viscosity(kP) 10 15 T200P − T35kP (° C.) 483 486 492 480 487 Anneal Point (° C.)− Softening −213.4 −220.3 −221.5 −227 −214.9 Point (° C. [Anneal Point(° C.) + Softening −878 −880 −884 −873 −881 Point (° C.)]/2 − T²⁰⁰[Anneal Point (° C.) + Softening −395 −394 −392 −393 −395 Point (°C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃ at 410°C. for 4 hours Thickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 648654 628 589 704 DOC (microns) 42 42 45 49 43 Ion-Exchange of Annealedparts in refined KNO₃ at 410° C. for 6 hours Thickness (mm) 1.0 1.0 1.01.0 1.0 Surface CS (MPa) 619 611 588 558 670 DOC (microns) 50 53 56 5951 Examples 41 42 43 44 45 Analyzed mol % 177CPK 177CPL 177CPM 177CPN177CPO SiO₂ 66.94 66.83 66.56 66.25 66.23 Al₂O₃ 8.93 9.03 8.96 8.96 8.97P₂O₅ 0.48 0.73 0.94 1.19 1.38 Na₂O 16.58 16.37 16.53 16.55 16.50 K₂O2.98 2.92 2.95 2.98 2.91 MgO 0.01 0.01 0.01 0.01 0.01 ZnO 3.97 3.99 3.933.95 3.89 CaO 0.02 0.02 0.02 0.02 0.02 SnO₂ 0.10 0.10 0.10 0.10 0.09R₂O—Al₂O₃ 10.63 10.27 10.51 10.57 10.44 R₂O:Al₂O₃ 2.19 2.14 2.17 2.182.16 Density (g/cm³) 2.516 2.513 2.51 2.511 2.509 Strain Point (° C.)503 503 504 502 501 Anneal Point (° C.) 550 551 550 550 548 SofteningPoint (° C.) 762.6 770.2 767.9 768.2 768.6 [Anneal Point (° C.) +Softening 656 661 659 659 658 Point (° C.)]/2 Coefficient of Thermal99.7 98.4 98.8 99.6 99 Expansion × 10⁻⁷ (1/° C.) Stress OpticalCoefficient 3.063 3.081 3.074 3.066 3.098 (nm/mm/MPa) Refractive Index1.5078 1.5071 1.5064 1.5063 1.5052 200 Poise Temperature (° C.) 15331543 1532 1532 1529 35000 Poise Temperature (° C.) 1051 1055 1055 10461058 200000 Poise Temperature (° C.) 954 957 958 948 961 LiquidusTemperature (° C.) 865 880 860 855 880 Liquidus Viscosity (kP) 1510 11061381 2150 1242 Zircon Breakdown Temperature (° C.) Zircon BreakdownViscosity (kP) T200P − T35kP (° C.) 482 487 477 486 471 Anneal Point (°C.) − Softening −212.6 −219.2 −217.9 −218.2 −220.6 Point (° C. [AnnealPoint (° C.) + Softening −877 −882 −874 −873 −871 Point (° C.)]/2 − T²⁰⁰[Anneal Point (° C.) + Softening −395 −395 −396 −387 −400 Point (°C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃ at 410°C. for 4 hours Thickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 670680 689 667 670 DOC (microns) 47 48 50 53 53 Ion-Exchange of Annealedparts in refined KNO₃ at 410° C. for 6 hours Thickness (mm) 1.0 1.0 1.01.0 1.0 Surface CS (MPa) 632 643 650 634 627 DOC (microns) 57 56 60 6366 Examples 46 47 48 49 50 Analyzed mol % 177CPP 177CPQ 177CPR 177CPS177CPT SiO₂ 67.05 67.31 67.11 66.71 66.50 Al₂O₃ 8.94 8.95 8.98 9.01 8.99P₂O₅ 0.24 0.46 0.69 0.94 1.17 Na₂O 16.41 16.15 16.09 16.29 16.25 K₂O3.01 2.90 2.90 2.89 2.91 MgO 4.20 4.09 4.09 4.02 4.03 ZnO 0.00 0.00 0.000.00 0.00 CaO 0.05 0.05 0.05 0.05 0.05 SnO₂ 0.10 0.10 0.10 0.10 0.10R₂O—Al₂O₃ 10.47 10.10 10.00 10.17 10.17 R₂O:Al₂O₃ 2.17 2.13 2.11 2.132.13 Density (g/cm³) 2.455 2.451 2.451 2.45 2.449 Strain Point (° C.)505 507 509 506 505 Anneal Point (° C.) 552 554 556 554 552 SofteningPoint (° C.) 771.1 777.2 778.8 776.6 776.4 [Anneal Point (° C.) +Softening 662 666 667 665 664 Point (° C.)]/2 Coefficient of Thermal99.7 98.8 98.9 98.6 98.7 Expansion × 10⁻⁷ (1/° C.) Stress OpticalCoefficient 2.828 2.853 2.87 2.877 2.906 (nm/mm/MPa) Refractive Index1.5032 1.5019 1.5019 1.5011 1.5007 200 Poise Temperature (° C.) 15491559 1555 1560 1562 35000 Poise Temperature (° C.) 1061 1074 1074 10671079 200000 Poise Temperature (° C.) 963 975 974 965 978 LiquidusTemperature (° C.) <780 835 845 855 885 Liquidus Viscosity (kP) >2.4E74821 2651 3054 1176 Zircon Breakdown Temperature (° C.) Zircon BreakdownViscosity (kP) T200P − T35kP (° C.) 488 484 481 493 484 Anneal Point (°C.) − Softening −219.1 −223.2 −222.8 −222.6 −224.4 Point (° C. [AnnealPoint (° C.) + Softening −888 −893 −888 −895 −898 Point (° C.)]/2 − T²⁰⁰[Anneal Point (° C.) + Softening −400 −409 −407 −402 −414 Point (°C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃ at 410°C. for 4 hours Thickness (mm) 1.0 1.0 1.0 1.0 1.0 Surface CS (MPa) 730727 725 708 673 DOC (microns) 44 45 47 56 51 Ion-Exchange of Annealedparts in refined KNO₃ at 410° C. for 6 hours Thickness (mm) 1.0 1.0 1.01.0 1.0 Surface CS (MPa) 688 698 676 717 634 DOC (microns) 52 54 56 4861 Examples 51 52 53 54 55 Analyzed mol % 177CPU 519KRU 519KSG 519KSN519KST SiO₂ 66.25 66.75 67.51 66.61 65.65 Al₂O₃ 9.03 9.68 9.29 8.07 8.00P₂O₅ 1.41 0.02 0.00 0.00 0.95 Na₂O 16.20 15.97 16.00 16.62 16.69 K₂O2.91 2.84 2.86 2.96 2.96 MgO 4.06 2.01 2.07 5.51 5.58 ZnO 0.00 0.00 0.000.00 0.00 CaO 0.05 2.62 2.17 0.12 0.06 SnO₂ 0.10 0.10 0.10 0.10 0.11R₂O—Al₂O₃ 10.08 9.12 9.56 11.51 11.65 R₂O:Al₂O₃ 2.12 1.94 2.03 2.43 2.46Density (g/cm³) 2.448 2.47 2.46 2.46 2.46 Strain Point (° C.) 505 503500 487 487 Anneal Point (° C.) 552 548 545 532 531 Softening Point (°C.) 777.5 764 761 754 748 [Anneal Point (° C.) + Softening 665 656 653643 640 Point (° C.)]/2 Coefficient of Thermal 99.2 97.9 102.4 Expansion× 10⁻⁷ (1/° C.) Stress Optical Coefficient 2.846 2.844 2.853 2.824 2.835(nm/mm/MPa) Refractive Index 1.4996 1.507 1.507 1.505 1.502 200 PoiseTemperature (° C.) 1565 1536 1545 1508 1509 35000 Poise Temperature (°C.) 1071 1049 1047 1035 1038 200000 Poise Temperature (° C.) 969 952 950940 943 Liquidus Temperature (° C.) 1015 740 <780 760 905 LiquidusViscosity (kP) 56488 >13929 21430 449 Zircon Breakdown Temperature (°C.) 1090 1115 1100 1105 Zircon Breakdown Viscosity (kP) 18.6 12.8 13.012.4 T200P − T35kP (° C.) 495 487 498 472 471 Anneal Point (° C.) −Softening −225.5 −215.8 −216 −222 −217 Point (° C. [Anneal Point (°C.) + Softening −901 −880 −892 −865 −869 Point (° C.)]/2 − T²⁰⁰ [AnnealPoint (° C.) + Softening −406 −393 −394 −392 −398 Point (° C.)]/2 −T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃ at 410° C. for 4hours Thickness (mm) 1.0 0.55 0.55 0.55 Surface CS (MPa) 708 747 690 648DOC (microns) 51 32 37 45 Ion-Exchange of Annealed parts in refined KNO₃at 410° C. for 6 hours Thickness (mm) 1.0 0.55 0.55 0.55 Surface CS(MPa) 679 708 654 608 DOC (microns) 64 39 45 53 Examples 56 57 58 59Analyzed mol % 519KTA 519KTE 519KTH 519KTI SiO₂ 65.60 65.61 65.61 65.89Al₂O₃ 8.24 8.57 8.59 8.61 P₂O₅ 0.97 0.98 0.98 0.69 Na₂O 16.62 16.7016.72 16.68 K₂O 2.76 2.44 2.41 2.40 MgO 5.64 5.55 5.53 5.56 ZnO 0.000.00 0.00 0.00 CaO 0.05 0.05 0.05 0.05 SnO₂ 0.11 0.11 0.11 0.11R₂O—Al₂O₃ 11.15 10.56 10.54 10.47 R₂O:Al₂O₃ 2.35 2.23 2.23 2.22 Density(g/cm³) 2.45 2.45 2.45 2.45 Strain Point (° C.) 495 502 505 504 AnnealPoint (° C.) 540 549 550 551 Softening Point (° C.) 757 770 774 771[Anneal Point (° C.) + Softening 649 659 662 661 Point (° C.)]/2Coefficient of Thermal 100.1 100.1 100.1 Expansion × 10⁻⁷ (1/° C.)Stress Optical Coefficient 2.848 2.866 2.871 (nm/mm/MPa) RefractiveIndex 1.503 1.503 1.503 200 Poise Temperature (° C.) 1511 1530 153535000 Poise Temperature (° C.) 1047 1062 1061 200000 Poise Temperature(° C.) 951 967 966 Liquidus Temperature (° C.) 915 915 LiquidusViscosity (kP) 425 616 Zircon Breakdown Temperature (° C.) 1105 1115Zircon Breakdown Viscosity (kP) 14.2 15.4 T200P − T35kP (° C.) 465 468474 Anneal Point (° C.) − Softening −217 −220.89 −224 −220.08 Point (°C. [Anneal Point (° C.) + Softening −863 −868 −874 Point (° C.)]/2 −T²⁰⁰ [Anneal Point (° C.) + Softening −398 −400 −400 Point (° C.)]/2 −T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃ at 410° C. for 4hours Thickness (mm) 0.55 0.55 0.55 Surface CS (MPa) 656 721 728 DOC(microns) 42 40.7 41 Ion-Exchange of Annealed parts in refined KNO₃ at410° C. for 6 hours Thickness (mm) 0.55 0.55 0.55 Surface CS (MPa) 633677 695 DOC (microns) 51 50 51 Examples 60 61 62 63 Analyzed mol %519KTL 519KTP 519KTR 519KTT SiO₂ 66.32 66.55 66.30 66.00 Al₂O₃ 8.61 8.658.83 9.22 P₂O₅ 0.20 0.02 0.02 0.01 Na₂O 16.72 16.67 16.73 16.71 K₂O 2.402.39 2.46 2.39 MgO 5.59 5.55 4.34 2.46 ZnO 0.00 0.01 1.18 3.06 CaO 0.050.05 0.04 0.03 SnO₂ 0.11 0.11 0.11 0.11 R₂O—Al₂O₃ 10.52 10.41 10.36 9.88R₂O:Al₂O₃ 2.22 2.20 2.17 2.07 Density (g/cm³) 2.46 2.48 2.49 StrainPoint (° C.) 505 506 510 513 Anneal Point (° C.) 552 551 557 558Softening Point (° C.) 771 774 775 776 [Anneal Point (° C.) + Softening661 663 666 667 Point (° C.)]/2 Coefficient of Thermal 98.8 98.8Expansion × 10⁻⁷ (1/° C.) Stress Optical Coefficient 2.840 2.863 2.8542.959 (nm/mm/MPa) Refractive Index 1.504 1.504 1.505 1.507 200 PoiseTemperature (° C.) 1534 1532 1527 1534 35000 Poise Temperature (° C.)1060 1059 1061 1060 200000 Poise Temperature (° C.) 964 963 965 966Liquidus Temperature (° C.) <790 <780 Liquidus Viscosity(kP) >17010 >27715 Zircon Breakdown Temperature (° C.) 1075 1095 ZirconBreakdown Viscosity (kP) 26.9 20.1 T200P − T35kP (° C.) 474 473 466 474Anneal Point (° C.) − Softening −219.49 −223 −217.8 −218 Point (° C.[Anneal Point (° C.) + Softening −873 −870 −861 −867 Point (° C.)]/2 −T²⁰⁰ [Anneal Point (° C.) + Softening −399 −396 −395 −393 Point (°C.)]/2 − T³⁵⁰⁰⁰ Ion-Exchange of Annealed parts in refined KNO₃ at 410°C. for 4 hours Thickness (mm) 0.55 Surface CS (MPa) 735 DOC (microns) 37Ion-Exchange of Annealed parts in refined KNO₃ at 410° C. for 6 hoursThickness (mm) 0.55 Surface CS (MPa) 690 DOC (microns) 46 Examples 64 6566 67 Analyzed mol % 519KTY 519KUN 519KVP 519KVW SiO₂ 65.64 66.49 65.4565.91 Al₂O₃ 9.46 8.69 9.52 9.63 P₂O₅ 0.00 0.00 0.50 0.03 Na₂O 16.7716.54 16.71 16.72 K₂O 2.45 2.39 2.09 2.09 MgO 0.18 5.61 2.46 2.47 ZnO5.37 0.01 3.06 2.89 CaO 0.02 0.05 0.00 0.02 SnO₂ 0.10 0.21 0.21 0.21R₂O—Al₂O₃ 9.76 10.24 9.28 9.18 R₂O:Al₂O₃ 2.03 2.18 1.97 1.95 Density(g/cm³) 2.54 2.508 Strain Point (° C.) 519 507 525 Anneal Point (° C.)564 553 571 Softening Point (° C.) 774 776 794 [Anneal Point (° C.) +Softening 669 665 683 Point (° C.)]/2 Coefficient of Thermal 97.2Expansion × 10⁻⁷ (1/° C.) Stress Optical Coefficient 3.122 2.865(nm/mm/MPa) Refractive Index 1.513 1.505 1.507 200 Poise Temperature (°C.) 1528 1534 1534 35000 Poise Temperature (° C.) 1055 1066 1073 200000Poise Temperature (° C.) 963 971 978 Liquidus Temperature (° C.)Liquidus Viscosity (kP) 7989 Zircon Breakdown Temperature (° C.) 1075Zircon Breakdown Viscosity (kP) T200P − T35kP (° C.) 473 468 461 AnnealPoint (° C.) − Softening −209.6 −223 −223 Point (° C. [Anneal Point (°C.) + Softening −859 −870 −852 Point (° C.)]/2 − T²⁰⁰ [Anneal Point (°C.) + Softening −386 −402 −390 Point (° C.)]/2 − T35000 Ion-Exchange ofAnnealed parts in refined KNO₃ at 410° C. for 4 hours Thickness (mm)Surface CS (MPa) DOC (microns) Ion-Exchange of Annealed parts in refinedKNO₃ at 410° C. for 6 hours Thickness (mm) Surface CS (MPa) DOC(microns)

Examples 68-77

Examples 68-77 are exemplary glass compositions according to one or moreembodiments of this disclosure. The glass compositions (in mol %) ofExamples 68-77 are provided in Table 3, along with strain pointtemperature (as measured by beam bending viscometer), annealing pointtemperature (as measured by beam bending viscometer), softening pointtemperature (as measured by fiber elongation), sag temperature,temperature at log 11 viscosity (Poise), T₂₀₀, T₃₅₀₀₀, T₂₀₀₀₀₀, density,CTE, liquidus viscosity, zircon breakdown temperature, and zirconbreakdown viscosity.

TABLE 3 Examples 68 69 70 71 72 Analyzed mol % 10/90 20/80 30/70 40/6050/50 SiO₂ 65.34 65.41 65.49 65.57 65.64 Al₂O₃ 9.6 9.56 9.52 9.48 9.44P₂O₅ 0.44 0.39 0.34 0.29 0.25 Na₂O 16.87 16.86 16.84 16.82 16.81 K₂O2.13 2.16 2.19 2.22 2.25 MgO 2.52 2.52 2.51 2.5 2.5 ZnO 2.88 2.9 2.922.94 2.96 SnO₂ 0.21 0.2 0.19 0.18 0.17 Strain point(° C.) 524 523 521520 519 Anneal Point(° C.) 570 568 567 566 565 Softening 792 790 789 787785 point(° C.) Sag temp (° C.) 676 675 673 672 671 T at log 11 (° C.)636 634 633 632 630 [Anneal Point 681 679 678 676 675 (° C.) + SofteningPoint (° C.)]/2 200 Poise 977 976 915 973 972 Temperature (° C.) 35000Poise 1072 1070 1069 1068 1067 Temperature (° C.) 200000 Poise 1534 15341534 1534 1534 Temperature (° C.) Density (g/cm³) 2.506 2.504 2.502 2.52.498 Coefficient of 97.4 97.5 97.7 97.8 98 Thermal Expansion × 10⁻⁷(1/° C.) Liquidus 9962 11934 13907 15879 17852 viscosity (kP) Zircon1077 1077 1077 1077 1077 Breakdown Temperature (° C.) Zircon 5 9 12 1518 Breakdown Temperature (° C.)—35000 Poise Temperature (° C.) Examples73 74 75 76 77 Analyzed mol % SiO₂ 65.72 65.79 65.87 65.94 65.26 Al₂O₃9.39 9.35 9.31 9.27 9.43 P₂O₅ 0.2 0.15 0.1 0.05 0.69 Na₂O 16.79 16.7716.76 16.74 17.02 K₂O 2.28 2.3 2.38 2.36 2.06 MgO 2.49 2.48 2.48 2.472.53 ZnO 2.98 3 3.02 3.04 2.82 SnO₂ 0.15 0.14 0.13 0.12 0.2 Strainpoint(° C.) 518 516 515 514 527 Anneal Point(° C.) 563 562 561 559 572Softening 783 781 780 779 792 point(° C.) Sag temp (° C.) 669 668 666665 T at log 11 (° C.) 629 628 626 625 638 [Anneal Point 673 672 670 669682 (° C.) + Softening Point (° C.)]/2 200 Poise 971 970 968 967 1542Temperature (° C.) 35000 Poise 1065 1064 1063 1062 1074 Temperature (°C.) 200000 Poise 1534 1534 1534 1534 980 Temperature (° C.) Density(g/cm³) 2.496 2.494 2.492 2.490 Coefficient of 98.2 98.3 98.5 98.6Thermal Expansion × 10⁻⁷ (1/° C.) Liquidus 19825 21797 23770 25742 3177viscosity (kP) Zircon 1077 1077 1077 1077 1090 Breakdown Temperature (°C.) Zircon 22 25 28 31 16 Breakdown Temperature (° C.)—35000 PoiseTemperature (° C.)

FIG. 10 is a log viscosity curve as a function of temperature forExamples 63, and 66, modeled Example 72, along with a known soda limesilicate glass composition. For comparison, a known alkalialuminosilicate glass composition (Comparative Ex. A) is shown in Table2.

TABLE 2 Comparative Examples Ex. A Analyzed mol % SiO₂ 69.2 Al₂O₃ 8.5P₂O₅ Na₂O 13.9 K₂O 1.2 MgO 6.4 ZnO CaO 0.5 SnO₂ 0.2 R₂O—Al₂O₃ 6.6R₂O:Al₂O₃ 1.78 Density (g/cm³) 2.44 Strain Point (° C.) 560 Anneal Point(° C.) 609 Softening Point (° C.) 844 [Anneal Point (° C.) + SofteningPoint 726.5 (° C.)]/2 Coefficient of Thermal Expansion × 83.6 10⁻⁷ (1/°C.) Stress Optical Coefficient (nm/mm/MPa) Refractive Index 200 PoiseTemperature (° C.) 1047 35000 Poise Temperature (° C.) 1145 200000 PoiseTemperature (° C.) 1535 Liquidus Temperature (° C.) Liquidus Viscosity(kP) 1729 Zircon Breakdown Temperature (° C.) Zircon Breakdown Viscosity(kP) T200P − T35kP (° C.) 98 Anneal Point (° C.) − Softening Point −235(° C. [Anneal Point (° C.) + Softening Point −320.5 (° C.)]/2 − T²⁰⁰[Anneal Point (° C.) + Softening Point −418.5 (° C.)]/2 − T³⁵⁰⁰⁰

As shown in Table 2, Comparative Ex. A is a alkali aluminosilicate glasscomposition that exhibits significantly different attributes than theinventive glass compositions described herein. In particular ComparativeEx. A exhibits a relationship of (anneal point+softening point)/2 thatis greater than 725° C. In addition, Comparative Ex. A exhibits adifference between T₂₀₀ and T₃₅₀₀₀ is significantly less than 400° C.,the relationship [(anneal point (° C.)+softening point (° C.))/2−T₂₀₀]greater than −800° C. In addition, Comparative Ex. A exhibits a sagtemperature of about 723° C.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention.

Aspect (1) of this disclosure pertains to a glass article comprising aglass composition, the glass composition comprising: SiO₂ in an amountin a range from about 63 mol % to about 75 mol %; Al₂O₃ in an amount ina range from about 7 mol % to about 13 mol %; R₂O in an amount fromabout 13 mol % to about 24 mol %; P₂O₅ in an amount in a range fromabout 0 mol % to about 3 mol %; wherein the glass composition comprisesone or both of MgO and ZnO, wherein the amount of MgO is in a range fromabout 0 mol % to about 7 mol % and ZnO is present in an amount in arange from about 0 mol % to about 7 mol %, wherein the glass articlecomprises an anneal point (° C.) and a softening point (° C.), and therelationship of (anneal point+softening point)/2 is in a range fromabout 625° C. to about 725° C.

Aspect (2) of this disclosure pertains to the glass article of Aspect(1), wherein the glass article comprises a temperature (° C.) at aviscosity of 200 poises (T₂₀₀) and a temperature (° C.) at a viscosityof 35000 poise (T₃₅₀₀₀), and wherein T₂₀₀−T₃₅₀₀₀ is in a range fromabout 400° C. to about 600° C.

Aspect (3) of this disclosure pertains to the glass article of Aspect(1) or Aspect (2), wherein the glass article comprises a temperature (°C.) at a viscosity of 200 poises (T₂₀₀), and wherein the differencebetween the relationship (anneal point+softening point)/2 and T₂₀₀ isless than −800° C.

Aspect (4) of this disclosure pertains to the glass article of any oneof Aspects (1) through (3), wherein the glass article comprises atemperature (° C.) at a viscosity of 35000 poises (T₃₅₀₀₀), and whereinthe difference between the relationship (anneal point+softening point)/2and T₃₅₀₀₀ is less than −300° C.

Aspect (5) of this disclosure pertains to the glass article of any oneof Aspects (2) through (4), wherein either one of or both T₂₀₀ andT₃₅₀₀₀ are greater than about 1030° C.

Aspect (6) of this disclosure pertains to the glass article of any oneof Aspects (1) through (5), wherein the glass article comprises a sagtemperature in a range from about 620° C. to about 720° C.

Aspect (7) of this disclosure pertains to the glass article of any oneof Aspects (1) through (6), wherein the amount of Al₂O₃ is in a rangefrom about 8 mol % to about 11 mol %, the amount of Na₂O is in an amountin a range from about 12 mol % to about 18 mol %, the amount of K₂O isin a range from about 1 mol % to about 3.5 mol %.

Aspect (8) of this disclosure pertains to the glass article of any oneof Aspects (1) through (7), further comprising CaO in an amount in arange from about 0.01 mol % to about 4 mol %.

Aspect (9) of this disclosure pertains to the glass article of any oneof Aspects (1) through (8), wherein MgO is present in an amount in arange from about 0 mol % to about 3 mol %.

Aspect (10) of this disclosure pertains to the glass article of any oneof Aspects (1) through (9), wherein ZnO is present in an amount in arange from about 0 mol % to about 5 mol %.

Aspect (11) of this disclosure pertains to the glass article of any oneof Aspects (1) through (10), wherein the relationship (annealpoint+softening point)/2 is less than about 700° C.

Aspect (12) of this disclosure pertains to the glass article of any oneof Aspects (1) through (11), further comprising a liquidus viscositygreater than about 100 kP.

Aspect (13) of this disclosure pertains to the glass article of any oneof Aspects (1) through (12), further comprising a zircon breakdownviscosity or less than about 35 kP.

Aspect (14) of this disclosure pertains to the glass article of any oneof Aspects (1) through (13), wherein the glass article is strengthened.

Aspect (15) of this disclosure pertains to the glass article of any oneof Aspects (1) through (14), wherein the glass article is fusion formed.

Aspect (16) of this disclosure pertains to an aluminosilicate glassarticle comprising: a glass composition comprising Al₂O₃ in an amountgreater than 2 mol %; and wherein the glass article comprises an annealpoint (° C.) and a softening point (° C.), and the relationship of(anneal point+softening point)/2 is in a range from about 625° C. toabout 725° C.

Aspect (17) of this disclosure pertains to the glass article of Aspect(16), wherein the glass composition comprises a total amount of alkalimetal oxides (R₂O) that is equal to or greater than about 5 mol %.

Aspect (18) of this disclosure pertains to the glass article of Aspect(16) or Aspect (17), wherein the glass composition comprises one or bothof MgO and ZnO, wherein the amount of MgO is in a range from about 0 mol% to about 7 mol % and ZnO is present in an amount in a range from about0 mol % to about 7 mol %.

Aspect (19) of this disclosure pertains to the glass article of any oneof Aspects (16) through (18), wherein the total amount of amount ofalkali metal oxides is in a range from about 5 mol % to about 20 mol %.

Aspect (20) of this disclosure pertains to the glass article of any oneof Aspects (16) through (19), further comprising a temperature at aviscosity of 35 kilopoise of greater than about 1000° C.

Aspect (21) of this disclosure pertains to the glass article of any oneof Aspects (16) through (20), further comprising a temperature at aviscosity of 200 kilopoise of greater than about 900° C.

Aspect (22) of this disclosure pertains to the glass article of any oneof Aspects (16) through (21), further comprising an anneal point of lessthan about 580° C.

Aspect (23) of this disclosure pertains to the glass article of any oneof Aspects (16) through (22), further comprising a strain point of lessthan about 530° C.

Aspect (24) of this disclosure pertains to the glass article of any oneof Aspects (16) through (23), further comprising a density of about 2.6g/cm³ or less.

Aspect (25) of this disclosure pertains to the glass article of any oneof Aspects (16) through (24), further comprising a softening point in arange from about 725° C. and 860° C.

Aspect (26) of this disclosure pertains to the glass article of any oneof Aspects (16) through (25), wherein the glass article is strengthened.

Aspect (27) of this disclosure pertains to the glass article of any oneof Aspects (16) through (26), wherein the glass article is fusionformed.

Aspect (28) of this disclosure pertains to a vehicle comprising: a bodydefining an interior and an opening in communication with the interior;a glass article disposed in the opening, the article comprising a glasscomposition, the glass composition comprising Al₂O₃ in an amount greaterthan 2 mol %, an anneal point (° C.), a softening point (° C.), and therelationship of (anneal point+softening point)/2 in a range from about625° C. to about 725° C.

Aspect (29) of this disclosure pertains to the vehicle of Aspect (28),wherein the glass article comprises a glass composition, the glasscomposition comprising a total amount of alkali metal oxide in an amountof about 16 mol % or greater, and a sag temperature in a range fromabout 600° C. to about 700° C.

Aspect (30) of this disclosure pertains to the vehicle of Aspect (28) orAspect (29), where the glass composition further comprises Al₂O₃ in anamount greater than 4 mol %.

Aspect (31) of this disclosure pertains to the vehicle of any one ofAspects (28) through (30), wherein the glass composition furthercomprises an alkali metal oxide selected from Li₂O, Na₂O and K₂O,wherein the alkali metal oxide is present in an amount greater thanabout 5 mol %.

Aspect (32) of this disclosure pertains to the vehicle of Aspect (31),wherein the glass composition further comprises a total amount of amountof alkali metal oxides (R₂O=Li₂O+Na₂O+K₂O) in a range from about 5 mol %to about 24 mol %.

Aspect (33) of this disclosure pertains to the vehicle of any one ofAspects (28) through (32), wherein the glass article further comprises atemperature at a viscosity of 35 kilopoise of greater than about 1000°C.

Aspect (34) of this disclosure pertains to the vehicle of any one ofAspects (28) through (33), wherein the glass article further comprises atemperature at a viscosity of 200 kilopoise of greater than about 900°C.

Aspect (35) of this disclosure pertains to the vehicle of any one ofAspects (28) through (34), wherein the glass article further comprisesan anneal point of less than about 600° C.

Aspect (36) of this disclosure pertains to the vehicle of any one ofAspects (28) through (35), wherein the glass article further comprises astrain point of less than about 550° C.

Aspect (37) of this disclosure pertains to the vehicle of any one ofAspects (28) through (36), wherein the glass article further comprises adensity of about 2.6 g/cm³ or less.

Aspect (38) of this disclosure pertains to the vehicle of any one ofAspects (28) through (37), wherein the glass article further comprises asoftening point is in a range from about 725° C. and 860° C.

Aspect (39) of this disclosure pertains to the vehicle of any one ofAspects (28) through (38), wherein the glass article is strengthened.

Aspect (40) of this disclosure pertains to the vehicle of any one ofAspects (28) through (39), wherein the glass article further is fusionformed.

Aspect (41) of this disclosure pertains to a laminate comprising: afirst glass layer; an interlayer disposed on the first glass layer; anda second glass layer disposed on the interlayer opposite the first glasslayer wherein either one of or both the first glass layer and the secondglass layer comprises the glass article according to any one of Aspects(1) through (15)

Aspect (42) of this disclosure pertains to the laminate of Aspect (41),wherein either one or both the first glass layer and the second glasslayer comprise a thickness less than about 1.6 mm.

Aspect (43) of this disclosure pertains to a laminate comprising: afirst glass layer; an interlayer disposed on the first glass layer; anda second glass layer disposed on the interlayer opposite the first glasslayer wherein the second glass layer comprises the glass articleaccording to any one of Aspects (1) through (15).

Aspect (44) of this disclosure pertains to the laminate of Aspect (43),wherein the first glass layer comprises a thickness of 1.6 mm orgreater, and the second glass layer comprises a thickness less thanabout 1.6 mm.

Aspect (45) of this disclosure pertains to a method for forming alaminate comprising: stacking a first glass article, and a second glassarticle according to any one of Aspects (1) through (27) to form astack, wherein the first glass article has a different composition thanthe second glass article and comprises a first surface and an secondsurface that opposes the first surface, wherein the second glass articlecomprises a third surface and a fourth surface that opposes the thirdsurface, and wherein the second surface is adjacent to the third surfacein the stack; placing the stack on a mold; heating the stack to atemperature that is above an annealing point of the first glass articleto form a shaped stack; and placing an interlayer between the firstglass article and the second glass layer.

Aspect (46) of this disclosure pertains to the method of Aspect (45),the shaped stack comprises a gap between the second surface and thethird surface having a maximum distance of about 10 mm or less.

Aspect (47) of this disclosure pertains to the method of Aspect (46),wherein the maximum distance is about 5 mm or less.

Aspect (48) of this disclosure pertains to the method of Aspect (46),wherein the maximum distance is about 3 mm or less.

Aspect (49) of this disclosure pertains to a laminate comprising: afirst curved glass layer comprising a first major surface, a secondmajor surface opposing the first major surface, a first thicknessdefined as the distance between the first major surface and second majorsurface, and a first sag depth of about 2 mm or greater, the firstcurved glass layer comprising a first viscosity (poises); a secondcurved glass layer comprising a third major surface, a fourth majorsurface opposing the third major surface, a second thickness defined asthe distance between the third major surface and the fourth majorsurface, and a second sag depth of about 2 mm or greater, the secondcurved glass layer comprising a second viscosity; and an interlayerdisposed between the first curved glass layer and the second curvedglass layer and adjacent the second major surface and third majorsurface, wherein the first viscosity at 630° C. is greater than thesecond viscosity at a temperature of 630° C., wherein the first sagdepth is within 10% of the second sag depth and a shape deviationbetween the first glass layer and the second glass layer of ±5 mm orless as measured by an optical three-dimensional scanner, and whereinone of or both the first major surface and the fourth major surfacecomprises an optical distortion of less than 200 millidiopters asmeasured by an optical distortion detector using transmission opticsaccording to ASTM 1561, and wherein the third major surface or thefourth major surface comprises a membrane tensile stress of less than 7MPa as measured by a surface stressmeter, according to ASTM C1279.

Aspect (50) of this disclosure pertains to the laminate of Aspect (49),wherein the first curved glass layer comprises the glass article of anyone of Aspects (1) through (15).

Aspect (51) of this disclosure pertains to the laminate of Aspect (49),wherein the first curved glass layer comprises the glass article of anyone of Aspects (16) through (27).

Aspect (52) of this disclosure pertains to the laminate of Aspect (49)or Aspect (51), wherein, at a temperature of about 630° C., the firstviscosity is in a range from about 10 times the second viscosity toabout 750 times the second viscosity.

Aspect (53) of this disclosure pertains to the laminate of any one ofAspects (49) through (52), wherein the first thickness is less than thesecond thickness.

Aspect (54) of this disclosure pertains to the laminate of any one ofAspects (49) through (53), wherein the first thickness is from about 0.1mm to less than about 1.6 mm, and the second thickness is in a rangefrom about 1.6 mm to about 3 mm.

Aspect (55) of this disclosure pertains to the laminate of any one ofAspects (49) through (54), wherein first curved layer comprises a firstsag temperature and the second curved glass layer comprises a second sagtemperature that differs from the first sag temperature.

Aspect (56) of this disclosure pertains to the laminate of Aspect (55),wherein the magnitude of the difference between the first sagtemperature and the second sag temperature is in a range from about 30°C. to about 150° C.

Aspect (57) of this disclosure pertains to the laminate of any one ofAspects (49) through (56), wherein the shape deviation is about ±1 mm orless.

Aspect (58) of this disclosure pertains to the laminate of any one ofAspects (49) through (57), wherein the shape deviation is about ±0.5 mmor less

Aspect (59) of this disclosure pertains to the laminate of any one ofAspects (49) through (58), wherein the optical distortion is about 100millidiopters or less.

Aspect (60) of this disclosure pertains to the laminate of any one ofAspects (49) through (59), wherein the membrane tensile stress is about5 MPa or less.

Aspect (61) of this disclosure pertains to the laminate of any one ofAspects (49) through (60), wherein the first sag depth is in a rangefrom about 5 mm to about 30 mm.

Aspect (62) of this disclosure pertains to the laminate of any one ofAspects (49) through (61), wherein the third major surface or the fourthmajor surface comprises a surface compressive stress of less than 3 MPaas measured by a surface stress meter.

Aspect (63) of this disclosure pertains to the laminate of any one ofAspects (49) through (62), wherein the laminate is substantially free ofvisual distortion as measured by ASTM C1652/C1652M.

Aspect (64) of this disclosure pertains to the laminate of any one ofAspects (49) through (63), wherein the first curved glass layer isstrengthened.

Aspect (65) of this disclosure pertains to the laminate of Aspect (64),wherein the first curved glass layer is chemically strengthened,mechanically strengthened or thermally strengthened.

Aspect (66) of this disclosure pertains to the laminate of Aspect (64)or Aspect (65), wherein the second glass curved layer is unstrengthened.

Aspect (67) of this disclosure pertains to the laminate of Aspect (64)or Aspect (65), wherein the second curved glass layer is strengthened.

Aspect (68) of this disclosure pertains to the laminate of any one ofAspects (49) through (67), wherein the second curved glass layercomprises a soda lime silicate glass.

Aspect (69) of this disclosure pertains to the laminate of any one ofAspects (49) through (68), wherein the first curved glass layercomprises a first length and a first width, either one of or both thefirst length and the first width is about 0.25 meters or greater.

Aspect (70) of this disclosure pertains to the laminate of any one ofAspects (49) through (69), wherein the first curved glass layercomprises a first length, and a first width, and the second curved glasslayer comprises a second length that is within 5% of the first length,and a second width that is within 5% of the first width.

Aspect (71) of this disclosure pertains to the laminate of any one ofAspects (49) through (70), where the laminate is complexly curved.

Aspect (72) of this disclosure pertains to the laminate of any one ofAspects (49) through (71), wherein the laminate comprises automotiveglazing or architectural glazing.

Aspect (73) of this disclosure pertains to a vehicle comprising: a bodydefining an interior and an opening in communication with the interior;and the laminate of any one of Aspects (49) through (72) disposed in theopening.

Aspect (74) of this disclosure pertains to the vehicle of Aspect (73),wherein the laminate is complexly curved.

Aspect (75) of this disclosure pertains to a vehicle comprising anexterior surface and the glass article of any one of Aspects (1) through(15).

Aspect (76) of this disclosure pertains to a vehicle comprising anexterior surface and the glass article of any one of Aspects (16)through (27).

Aspect (77) of this disclosure pertains to the vehicle of Aspect (75) orAspect (76), wherein the exterior surface forms one of an engine blockcover, headlight cover, taillight cover, door panel cover, or pillarcover.

Aspect (78) of this disclosure pertains to a vehicle comprising aninterior surface and the glass article of any one of Aspects (1) through(15).

Aspect (79) of this disclosure pertains to a vehicle comprising aninterior surface and the glass article of any one of Aspects (16)through (27).

Aspect (80) of this disclosure pertains to the vehicle of Aspect (78) orAspect (79), wherein the interior surface forms one of a door trim, aseat back, a door panel, a dashboard, a center console, a floor board, arear view mirror and a pillar.

What is claimed is:
 1. A laminate, comprising: a first curved glasslayer comprising a first major surface, a second major surface opposingthe first major surface, a first thickness defined as a distance betweenthe first major surface and the second major surface, and a first sagdepth of 2 mm or greater; a second curved glass layer comprising a thirdmajor surface, a fourth major surface opposing the third major surface,a second thickness defined as a distance between the third major surfaceand the fourth major surface, and a second sag depth of 2 mm or greater;an interlayer disposed between the first curved glass layer and thesecond curved glass layer and adjacent the second major surface and thethird major surface; and wherein the first glass layer comprises a glasscomposition, the glass composition comprising: SiO₂ in an amount in arange from 63 mol % to 75 mol %; Al₂O₃ in an amount in a range from 7mol % to 13 mol %; R₂O in an amount from 13 mol % to 24 mol %, whereinR₂O═Li₂O+Na₂O+K₂O, P₂O₅ in an amount in a range from 0 mol % to 3 mol %;Fe₂O₃ in an amount in a range from 0.01 mol % to 1 mol %; wherein theglass composition comprises one or both of MgO and ZnO, wherein anamount of MgO is in a range from 0 mol % to 7 mol % and wherein anamount of ZnO is in a range from 0 mol % to 7 mol %, and wherein thefirst glass layer comprises an anneal point temperature, a softeningpoint temperature, and Tave=(the anneal point temperature+the softeningpoint temperature)/2 is in a range from 625° C. to 725° C.
 2. Thelaminate of claim 1, wherein the softening point temperature is in arange from 725° C. to 810° C.
 3. The laminate of claim 1, wherein thefirst glass layer comprises a first temperature T₂₀₀ at a viscosity of200 poises and a second temperature T₃₅₀₀₀ at a viscosity of 35000poises, and T₂₀₀−T₃₅₀₀₀ is in a range from 400° C. to 600° C.
 4. Thelaminate of claim 1, wherein the first glass layer comprises a firsttemperature T₂₀₀ at a viscosity of 200 poises, and a difference betweenTave and T₂₀₀ is less than −800° C.
 5. The laminate of claim 1, whereinthe first glass layer comprises a first temperature T₃₅₀₀₀ at aviscosity of 35000 poises, and a difference between Tave and T₃₅₀₀₀ isless than −300° C.
 6. The laminate of claim 3, wherein at least one ofT₂₀₀ or T₃₅₀₀₀ is greater than 1030° C.
 7. The laminate of claim 1,wherein the first glass layer comprises a sag temperature in a rangefrom 620° C. to 720° C.
 8. The laminate of claim 1, wherein the firstglass layer comprises Al₂O₃ in a range from 8 mol % to 11 mol %, Na₂O ina range from 12 mol % to 18 mol %, and K₂O in a range from 1 mol % to3.5 mol %.
 9. The laminate of claim 1, wherein Tave is less than 700° C.10. The laminate of claim 1, wherein the first glass layer isstrengthened.
 11. The laminate of claim 1, wherein the second thicknessis greater than the first thickness.
 12. The laminate of claim 1,wherein the first thickness is less than 1.6 mm.
 13. the laminate ofclaim 1, wherein the second thickness is in a range from 1.7 mm to 6 mm.14. The laminate of claim 1, wherein a membrane tensile stress at thethird major surface or the fourth major surface is less than 7 MPa asmeasured by a surface stress meter according to ASTM C1279.
 15. Thelaminate of claim 1, wherein the first sag depth is within 10% of thesecond sag depth.
 16. The laminate of claim 1, wherein a shape deviationbetween the first glass layer and the second glass layer is ±5 mm orless as measured by an optical three-dimensional scanner.
 17. Thelaminate of claim 1, wherein at least one of the first major surface orthe fourth major surface comprises an optical distortion of less than200 millidiopters as measured by an optical distortion detector usingtransmission optics according to ASTM
 1561. 18. The laminate of claim 1,wherein the first glass layer comprises a first viscosity at 630° C. andthe second glass layer comprises a second viscosity at 630° C. and thefirst viscosity is greater than the second viscosity.
 19. The laminateof claim 1, wherein a viscosity of the first glass layer at 630° C. isin a range from 2×10¹⁰ poises to 1×10¹³ poises.
 20. The laminate ofclaim 19, wherein a viscosity of the second glass layer at 630° C. is ina range from 1×10⁹ poises to 1×10¹⁰ poises.
 21. The laminate of claim 1,wherein the glass composition is substantially free of Li₂O.
 22. Thelaminate of claim 1, wherein the glass composition is substantially freeof B₂O₃.